JP2007043381A - Imaging apparatus, image processing apparatus, image processing method, and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imaging apparatus and the like capable of properly correcting brightness of a photographed image data. <P>SOLUTION: An image processor 7 of an imaging apparatus 100 comprises an index calculator 74 for calculating a natural light index that represents outdoor photographing degree for a photographed image data in natural light. It comprises a brightness correction amount calculator 75 which sets a plurality of temporary correction amounts for the photographed image data, based on a brightness analysis value and brightness representation target value of the photographed image data; and sets a mixing factor as a weight factor for multiplying the plurality of temporary correction amounts based on the natural light index, for calculating a brightness correction amount for the photographed image data based on the mixing factor and plurality of temporary correction amounts. It also comprises a brightness correction curve generator 76 which generates a brightness correction curve for converting the photographed image data based on the brightness correction amount and natural light index, and a picture quality corrector 72 for correcting brightness of the photographed image data according to the generated corrective curve. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an imaging apparatus, an image processing apparatus, an image processing method, and an image processing program that perform brightness correction processing of captured image data.

  Conventionally, a captured image obtained by photoelectrically reading an image acquired by an imaging device such as a digital camera or an image recorded on a photographic film such as a negative film is output (reproduced) by an output device such as a printer. To be done. In this way, when outputting (reproducing) a captured image using an output device, a so-called “dodging” process in which the low luminance portion and the high luminance portion of the image area are separately corrected and the dynamic range of the entire image is compressed. A method for suppressing the collapse of the bright part and the dark part, which occurs at the limit of the reproduction range of the output device by applying, is known (for example, see Patent Document 1).

On the other hand, the brightness of the captured image data is automatically adjusted so that the brightness of the main subject (for example, a human face area) of the captured image data is appropriately finished. In such a brightness adjustment method, there is a method for setting a correction amount and a correction curve for correcting the brightness of the captured image data based on the brightness obtained by analyzing the main subject of the captured image data. It is known (for example, refer to Patent Document 2).
JP 2005-72930 A JP 2002-247393 A

  However, if the brightness correction amount and correction curve for correcting the brightness of the captured image data are set based on the brightness of the main subject of the captured image data, the dynamic range is large, such as in backlight or strobe shooting scenes. In the scene, as the brightness correction amount is larger, there is a problem that a bright part and a dark part are crushed, a high-saturation color is saturated and crushed, and a hue is changed.

  Applying the above-described “Dodge” process as a solution to such a problem makes it difficult to maintain the brightness of the human face area appropriately, and the user's preference for the result of the remarkable “Dodge” process also varies. Because of this, improvements were desired. Furthermore, there is no difference in dynamic range between backlight and flash photography scenes, but in the first place the brightness and color type that should be wary of crushing in each scene is determined whether to make the image brighter or darker, that is, the human face There was an essential problem of depending on the accuracy of how the brightness of the area was detected.

  An object of the present invention is to appropriately correct the brightness of captured image data.

In order to solve the above-described problem, an invention according to claim 1 is an imaging apparatus that performs a process of acquiring a photographed image data by photographing a subject and optimizing brightness of a main subject in the photographed image data. And
Index calculating means for calculating a natural light index representing the degree of outdoor shooting by natural light of the captured image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generating means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculating means and the natural light index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 2 is an imaging device that performs processing for capturing a captured image data by capturing a subject and optimizing the brightness of a main subject in the captured image data.
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 3 is an imaging device that captures captured images and acquires captured image data, and performs processing for optimizing the brightness of the main subject in the captured image data.
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation means by the suppression coefficient;
A correction curve generating means for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplying means, the natural light index and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 4 is an imaging device that captures captured images and acquires captured image data, and performs processing for optimizing the brightness of the main subject in the captured image data.
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting means by the suppression coefficient;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of a plurality of new temporary correction amounts obtained by the multiplying means,
A correction amount calculating means for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of new temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 5 is an imaging device that captures captured image data by capturing a subject and performs a process of optimizing the brightness of a main subject in the captured image data.
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting means by the suppression coefficient;
Correction amount calculation means for calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

According to a sixth aspect of the present invention, in the imaging apparatus according to any one of the first to fifth aspects, the index calculating unit includes:
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. It is characterized by calculating.

The invention according to claim 7 is an image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
Index calculating means for calculating a natural light index representing the degree of outdoor shooting by natural light of the captured image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generating means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculating means and the natural light index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 8 is an image processing apparatus for performing processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 9 is an image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation means by the suppression coefficient;
A correction curve generating means for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplying means, the natural light index and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 10 is an image processing apparatus for performing processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents a degree of outdoor photographing by natural light of the captured image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the captured image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting means by the suppression coefficient;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of a plurality of new temporary correction amounts obtained by the multiplying means,
A correction amount calculating means for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of new temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 11 is an image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting means by the suppression coefficient;
Correction amount calculation means for calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means.

The invention according to claim 12 is the image processing apparatus according to any one of claims 7 to 11, wherein the index calculating means includes:
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. It is characterized by calculating.

The invention according to claim 13 is an image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculating step for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data;
A temporary correction amount setting step of setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of temporary correction amounts;
A correction curve generating step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculating step and the natural light index;
A correction step of correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation step.

The invention according to claim 14 is an image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting step for setting a plurality of provisional correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of temporary correction amounts;
A correction curve generation step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation step.

The invention according to claim 15 is an image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting step for setting a plurality of provisional correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation step for calculating a suppression coefficient for
A multiplication step of calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation step by the suppression coefficient;
A correction curve generating step for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplication step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation step.

The invention according to claim 16 is an image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A temporary correction amount setting step of setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation step for calculating a suppression coefficient for
A multiplication step of calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting step by the suppression coefficient;
Based on the natural light index calculated by the index calculation step, a mixing factor setting step for setting a mixing factor as a weighting factor to be multiplied to each of a plurality of new temporary correction amounts obtained by the multiplication step;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of new temporary correction amounts;
A correction curve generation step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation step.

The invention according to claim 17 is an image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A temporary correction amount setting step of setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation step for calculating a suppression coefficient for
A multiplication step of calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting step by the suppression coefficient;
A correction amount calculating step of calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication step and the plurality of temporary correction amounts;
A correction curve generation step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation step.

The invention according to claim 18 is the image processing method according to any one of claims 13 to 17, wherein the index calculation step includes:
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. It is characterized by calculating.

The invention according to claim 19 is an index calculation function for calculating a natural light index that represents a degree of outdoor shooting by natural light of captured image data in a computer;
A temporary correction amount setting function for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating function for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function and the natural light index;
An image processing program for realizing a correction function for correcting the brightness of the captured image data in accordance with a correction curve generated by the correction curve generation function.

The invention according to claim 20 is an index calculation function for calculating, in a computer, a natural light index that represents a degree of outdoor shooting by natural light of captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting function for setting a plurality of provisional correction amounts for the photographed image data based on a brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating function for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function, the natural light index and the luminance ratio index;
An image processing program for realizing a correction function for correcting the brightness of the captured image data in accordance with a correction curve generated by the correction curve generation function.

The invention according to claim 21 is an index calculation function for calculating, in a computer, a natural light index that represents a degree of outdoor shooting by natural light of captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting function for setting a plurality of provisional correction amounts for the photographed image data based on a brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculation function for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation function for calculating a suppression coefficient for
A multiplication function for calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation function by the suppression coefficient;
A correction curve generation function for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplication function, the natural light index, and the luminance ratio index;
An image processing program for realizing a correction function for correcting the brightness of the captured image data in accordance with a correction curve generated by the correction curve generation function.

The invention according to claim 22 is an index calculation function for calculating, in a computer, a natural light index that represents a degree of outdoor photographing by natural light of photographed image data, and a luminance ratio index that represents the size of the dynamic range of the photographed image data;
A temporary correction amount setting function for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation function for calculating a suppression coefficient for
A multiplication function for calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting function by the suppression coefficient;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient for multiplying each of a plurality of new temporary correction amounts obtained by the multiplication function;
A correction amount calculation function for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of new temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function, the natural light index and the luminance ratio index;
An image processing program for realizing a correction function for correcting the brightness of the captured image data in accordance with a correction curve generated by the correction curve generation function.

The invention according to claim 23 is an index calculation function for calculating, in a computer, a natural light index that represents a degree of outdoor shooting by natural light of captured image data, and a luminance ratio index that represents a dynamic range of the captured image data,
A temporary correction amount setting function for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation function for calculating a suppression coefficient for
A multiplication function for calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting function by the suppression coefficient;
A correction amount calculation function for calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication function and the plurality of temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function, the natural light index and the luminance ratio index;
An image processing program for realizing a correction function for correcting the brightness of the captured image data in accordance with a correction curve generated by the correction curve generation function.

According to a twenty-fourth aspect of the invention, in the image processing program according to any one of the nineteenth to twenty-third aspects,
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. It is characterized by calculating.

Next, terms in the present invention will be described.
“Optimizing the brightness of the main subject in the captured image data” means, for example, an output device (for example, a printer) that outputs the captured image data based on the brightness of the human face area that is the main subject of the captured image data. It is meant to be reproduced with the optimum brightness.

  The “brightness analysis value” of the captured image data is a numerical value indicating the average brightness of the image obtained by examining the distribution state of the pixel values. The “brightness analysis value” is desirably the brightness of the most important subject (main subject) in the captured image data. The search for the human face area is performed by collation in the color system using hue, saturation, and brightness. In order to obtain higher accuracy, it is preferable to use so-called “face detection” in which parts constituting the face, such as the eyes, nose, mouth, and face contour, are collated. Also, an exposure index indicating under / over shooting due to the exposure setting at the time of shooting may be calculated, and this exposure index may be used as a brightness analysis value. Further, the analysis method of the brightness analysis value is not limited to the analysis of the captured image data. For example, the brightness obtained by analyzing the automatic exposure information of the imaging apparatus and the additional information recorded of the automatic exposure information. It may be.

  The “reproduction target value” is, for example, a numerical value indicating the brightness necessary for the human face area, which is the main subject of the captured image data, to be optimally reproduced by the output device that outputs the captured image data. In other words, if the “brightness analysis value” of the captured image data is a value that approximates the “reproduction target value”, it means that the probability that the output device is optimally reproduced is high.

  The “temporary correction amount” is a numerical value that temporarily indicates the correction amount necessary to approximate the “brightness analysis value” to the “reproduction target value”. “Setting the temporary correction amount” means that a one-dimensional LUT (Look Up Table) in which the relationship between the “brightness analysis value” and the “temporary correction amount” is defined in advance is created. This means that the “temporary correction amount” is determined based on the “brightness analysis value”. Furthermore, “setting a plurality of provisional correction amounts” means “calculating brightness analysis values” under different conditions, and setting different “reproduction target values” (defining a plurality of one-dimensional LUTs. Or at least two “temporary correction amounts” are temporarily obtained.

  In the present invention, two one-dimensional LUTs for setting “temporary correction amounts” are defined, assuming brightness correction of a human face area in a backlight scene and a flash photography scene. Also, in a scene intermediate between a backlight scene and a flash shooting scene, at least one “temporary correction amount” setting one-dimensional LUT is assumed, assuming brightness correction of the entire image in the under and over shooting scenes. Is desirable.

  In order to make full use of the effects of the present invention, when creating a one-dimensional LUT for setting the “temporary correction amount”, the bright and dark portions are crushed, the high-saturation color is saturated and the hue is changed, etc. Prepare a large number of backlight scenes and flash photography scenes that actually cause the phenomenon as “learning images (also referred to as“ teacher data ”)” and observe the brightness of the human face area and the occurrence of these phenomena. It is desirable.

  “Natural light” is light that uses the sun as a light source, not an artificial light source such as steady light or flash light (referred to as “strobe”, “flash”, “speedlight”, etc.). Also called daylight. Daylight is a term that refers to an artificial light source with a color temperature (approximately 5500K) close to that of daylight, and is different from “natural light”.

  “Outdoor shooting degree” (also referred to as “natural light index”) is a numerical value that estimates whether or not the shot image data was taken using “natural light” and quantitatively shows the result. . Scenes that are shot using “natural light” and require brightness correction are often backlit scenes, and there is a probability that a high-luminance area or high-saturation sky blue area is distributed at the top of the screen, and a low-luminance area or skin color or green color is distributed at the bottom of the screen. high. On the other hand, for indoor or strobe shooting scenes that were shot without using “natural light”, a high-brightness area or low-saturation skin color area in the center of the screen, and a low-brightness area or low-brightness skin color or high saturation around the screen. Skin color tends to be distributed. Based on such experience, it is possible to quantitatively indicate whether or not the image is taken using “natural light” as “outdoor shooting degree”. It is desirable to use multivariate analysis as a statistical processing method for deriving one tendency from many variables such as the luminance at the top of the screen and the number of pixels of sky blue hue, the luminance at the bottom of the screen and the number of pixels of skin color hue.

The “mixing coefficient” is a weighting coefficient necessary for calculating one brightness correction amount from “a plurality of temporary correction values”. The definition of the brightness correction amount calculated based on the temporary correction amount and the mixing coefficient is shown in Equation (1). In equation (1), the i-th temporary correction amount is key_auto [i], the mixing coefficient to be multiplied by the temporary correction amount key_auto [i] is wgt [i], and the total number of temporary correction amounts is m.

  Based on the natural light index, “setting the mixing coefficient” means creating a one-dimensional LUT that defines the relationship between the “natural light index” and the “mixing coefficient” of each temporary correction amount in advance for the number of temporary correction amounts. This means that the “mixing coefficient” of each temporary correction amount is determined based on the one-dimensional LUT and the “natural light index”.

  When the natural light index indicates a high outdoor photographing value, a one-dimensional LUT (input: flesh color average luminance, output: temporary) assuming the brightness correction of the human face area in a backlight scene. The one-dimensional LUT is defined so that the “mixing coefficient” of (correction amount) becomes high.

  When the natural light index shows a numerical value of a low outdoor shooting degree, a one-dimensional LUT (input: flesh color average brightness, output: assumed) for setting a “temporary correction amount” assuming brightness correction of a human face area in a flash photography scene. The one-dimensional LUT is defined so that the “mixing coefficient” of the “temporary correction amount” is high.

  When the natural light index shows an ambiguous outdoor shooting degree value, a one-dimensional LUT for setting the “temporary correction amount” that assumes brightness correction of the entire image in under and over shooting scenes (input: overall average brightness, Alternatively, the one-dimensional LUT is defined so that the “mixing coefficient” of the under-over shooting index and output: provisional correction amount is high.

  “Generate a correction curve based on the brightness correction amount and the natural light index” means that the captured image is based on a predicted numerical value that quantitatively indicates whether or not the scene is captured using “natural light”. By changing the shape of the brightness correction curve while appropriately finishing the brightness of the main subject (e.g., human face area) of the data, the bright and dark parts are crushed, and the high-saturation color is saturated and crushed. This is to prevent the hue from changing.

  Scenes that are shot using “natural light” and require brightness correction are often backlit scenes, with a negative brightness correction amount. There is a high probability that the hue will change. On the other hand, for indoor or strobe shooting scenes that were shot without using “natural light”, the brightness correction amount is positive, the dark areas are crushed, the high-saturated skin color is saturated, and the hue is changed to yellow or red. Tend to change. Based on such experience, the shape of the brightness correction curve is changed.

  When the natural light index indicates a numerical value of a high outdoor shooting degree, a soft curve on the highlight side is defined on the assumption that the bright part in the backlight scene is crushed or the sky color of high saturation is saturated and crushed. On the other hand, when the natural light index indicates a numerical value of a low outdoor shooting degree, a shadow-side soft curve is defined on the assumption that a dark part in a flash shooting scene is crushed or a high-saturation skin color is saturated and crushed.

  “Calculate a luminance ratio index that represents the size of the dynamic range of the captured image data” and “Set the temporary correction amount based on the luminance ratio index and the brightness target value” The brightness correction amount set based on the brightness of the main subject is weakened so that the range is properly within the dynamic range of the output device that outputs the captured image data. This means that the correction amount is set. Note that the mixing coefficient of the temporary correction amount may be adjusted based on the luminance ratio index.

  Here, the “brightness ratio index indicating the size of the dynamic range” refers to the degree to which the brightness of the main subject area and the background area differ due to the light source conditions at the time of shooting, such as a backlight scene or flash shooting scene. Is a value that quantitatively indicates. For example, in a backlight scene, the photographer points the camera in the direction of the sun and photographs a person, so that the person face area is dark and the background area is a bright image. That is, if a difference value of brightness between the human face area and the background area is obtained, the difference value can be used as one of the indices. In general, it is known to obtain a difference value by drawing a histogram of image difference image data. When the captured image data is known as a backlight image in advance, the brightness correction amount and the correction curve can be corrected based on the “brightness ratio index indicating the size of the dynamic range”, and the bright portion of the captured image data can be corrected. In addition, it is possible to suppress a dark portion from being crushed, a high-saturation color to be saturated and crushed, and a hue from being changed.

  However, even if the backlit scene and the flash shooting scene are the same in dynamic range, the direction of brightness correction is completely opposite, so the process of correcting the human face area to the appropriate brightness is automated. To define the amount of provisional correction based on the luminance ratio index that represents the size of the dynamic range, depending on the predicted numerical value (natural light index) that quantitatively indicates whether there is a backlight scene or flash photography scene. I have to do it. Therefore, the “mixing coefficient” of the one-dimensional LUT (input: luminance ratio index, output: temporary correction amount) for setting the “temporary correction amount”, assuming brightness correction of a human face area in a backlight scene, is increased. A one-dimensional LUT that defines the relationship between the “natural light index” and the “mixing coefficient” of the temporary correction amount is defined.

  “Generate a correction curve based on the brightness correction amount, natural light index, and luminance ratio index” means a predicted numerical value (natural light) that quantitatively indicates whether or not the scene is shot using “natural light”. By changing the shape of the brightness correction curve while appropriately finishing the brightness of the main subject (for example, the human face area) of the captured image data according to the index) and the luminance ratio index representing the size of the dynamic range In other words, the bright and dark portions are crushed, the high saturation color is saturated and crushed, and the hue is suppressed.

  The “predetermined hue” is a hue of a high-saturation pixel that has a high probability of being saturated and crushed or changing to a hue such as cyan or green, and is a sky blue in a backlight scene, and a flesh color in an indoor shooting or strobe shooting scene. The “predetermined hue set based on the natural light index” is to change the hue of the high saturation pixel for counting the number of pixels based on the natural light index.

  The brightness correction amount calculation means analyzes the additional information recorded in the tag area of the photographed image data, and sets a new brightness correction amount by using the analyzed additional information as a supplement. Also good.

  According to the present invention, while correcting the brightness of the main subject in the photographed image data, it is possible to prevent the bright part and the dark part from being crushed, the color saturation due to high saturation, and the hue from being changed.

Hereinafter, embodiments 1 to 3 of the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
First, a configuration common to the first to third embodiments will be described.

  FIG. 1 shows a main part configuration of an imaging apparatus 100 according to Embodiments 1 to 3 of the present invention. As shown in FIG. 1, the imaging apparatus 100 includes a lens 1, an aperture 2, a CCD (Charge Coupled Device) 3, an analog processing circuit 4, an A / D converter 5, a temporary storage memory 6, an image processing unit 7, and header information. The processing unit 8, the storage device 9, the CCD drive circuit 10, the control unit 11, the operation unit 12, the display unit 13, the strobe drive circuit 14, the strobe 15, the focal length adjustment circuit 16, the automatic focus drive circuit 17, and the motor 20. The

  The optical system of the imaging apparatus 100 includes a lens 1 that can adjust the focus, a diaphragm 2 that adjusts the amount of light, and a CCD 3 that is a solid-state imaging device that converts subject information into an electrical signal.

  The subject information is imaged on the light receiving surface of the CCD 3 through the lens 1 and the diaphragm 2. The CCD 3 photoelectrically converts subject information into an electrical signal of an amount corresponding to the amount of incident light for each sensor in the CCD 3. A timing pulse is output from the CCD drive circuit 10 based on a control signal input from the control unit 11, and an electrical signal (imaging signal) accumulated in the CCD 3 is sequentially output by this timing pulse, and the analog processing circuit 4. Forwarded to

  The analog processing circuit 4 performs analog image pickup signal amplification and noise reduction processing. The A / D converter 5 converts the analog imaging signal input from the analog processing circuit 4 into a digital imaging signal (R, G, B signal). The digital R, G, B signals output from the A / D converter 5 are temporarily stored in the temporary storage memory 6. Hereinafter, the digital imaging signal is referred to as “photographed image data”.

  The image processing unit 7 performs display on the display unit 13, brightness correction of captured image data used for storage in the recording medium of the storage device 9, spectral sensitivity crosstalk correction, noise suppression, sharpening, white balance adjustment, and coloring. In addition to image quality improvement processing such as degree adjustment, processing such as image size change, trimming, and aspect conversion is performed. In the processing in the image processing unit 7, settings such as ON / OFF or an adaptive amount are switched according to operation information from the operation unit 12. For example, when operation information specifying brightness correction is input from the operation unit 12, the image processing unit 7 starts brightness correction processing (see FIG. 12). The internal configuration relating to the brightness correction by the image processing unit 7 will be described later with reference to FIG.

  The header information processing unit 8 performs a writing process of header information of the shooting information data generated by the image processing unit 7. The R, G, and B signals that have undergone the header information writing process are stored as image data in a recording medium by the storage device 9. The storage device 9 stores captured image image data and a control program for the imaging apparatus 100.

  The control unit 11 is configured by a CPU (Central Processing Unit) or the like, and performs an automatic focus driving circuit 17, a focal length adjusting circuit 16, and a CCD driving circuit for controlling the motor 20 that adjusts the focal length and focus (focus) of the lens 1. 10, the analog processing circuit 4, the temporary storage memory 6, the image processing unit 7, the display unit 13, and the strobe driving circuit 14 that drives the strobe 15 are controlled.

  The operation unit 12 includes buttons, cursor keys, and the like (not shown), and outputs operation information of the operation unit 12 by the user to the control unit 11. The display unit 13 displays captured image data on a liquid crystal display and displays settings and conditions related to shooting.

  FIG. 2 shows an internal configuration of the image processing unit 7. As illustrated in FIG. 2, the image processing unit 7 includes a preprocessing unit 70, a brightness correction unit 71, and an image quality correction unit 72.

  The preprocessing unit 70 performs spectral sensitivity crosstalk correction, dark current noise suppression, and temporary white balance adjustment on the captured image data input from the temporary storage memory 6, and the brightness correction unit 71 and the image quality correction unit 72. Output to.

  The brightness correction unit 71 includes an image analysis unit 73, an index calculation unit 74, a brightness correction amount calculation unit 75, and a brightness correction curve generation unit 76.

  The image analysis unit 73 calculates a brightness analysis value of the captured image data. The brightness analysis value is a numerical value indicating the average brightness of the photographed image data obtained by examining the distribution state of the pixel values of the photographed image data, and the most important subject (main subject) in the photographed image data. It is preferable that the brightness is. As the brightness analysis value, for example, an average value of luminance values of the entire captured image data (hereinafter referred to as “total average luminance”), an average luminance value in the skin color area of the captured image data (hereinafter referred to as “skin color average luminance”). .), An exposure index (index 6 described later) indicating under and over due to the exposure setting at the time of shooting.

  In the first to third embodiments, the index calculation unit 74 calculates a natural light index (an index 4 to be described later) that represents the degree of outdoor shooting with natural light of captured image data. In the second and third embodiments, the index calculation unit 74 calculates a luminance ratio index (an index 5 described later) that represents the size of the dynamic range of the captured image data. Further, in the third embodiment, the index calculation unit 74 calculates an exposure index (an index 6 to be described later) representing under and over due to the exposure setting at the time of shooting.

  The brightness correction amount calculation unit 75 calculates the brightness correction amount of the captured image data based on the brightness analysis value calculated by the image analysis unit 73 and the calculation result of the index calculation unit 74. The internal configuration of the brightness correction amount calculation unit 75 will be described in detail later with reference to FIG. 3 (Embodiment 1), FIG. 27 (Embodiment 2), and FIGS. 31 to 33 (Embodiment 3).

  The brightness correction curve generation unit 76 generates a brightness correction curve for converting photographed image data based on the brightness correction amount calculated by the brightness correction amount calculation unit 75.

  The image quality correction unit 72 corrects the brightness of the captured image data input from the preprocessing unit 70 in accordance with the brightness correction curve generated by the brightness correction curve generation unit 76. The captured image data whose brightness has been corrected is output to the header information processing unit 8 and the display unit 13.

  FIG. 3 shows an internal configuration of the brightness correction amount calculation unit 75 of the first embodiment. The brightness correction amount calculation unit 75 includes a temporary correction amount setting unit 101, a mixing coefficient setting unit 102, and a brightness correction amount calculation unit 103.

  The temporary correction amount setting unit 101 sets a temporary correction amount for the captured image data based on the brightness analysis value of the captured image data and the brightness reproduction target value. When n brightness analysis values are input from the image analysis unit 73, the temporary correction amount setting unit 101 corrects the correction amount (hereinafter referred to as “temporary”) to approximate each brightness analysis value to the reproduction target value. N correction amounts) are set.

  FIG. 4 shows a one-dimensional LUT (Look Up Table) that defines the relationship between the luminance ratio index and the temporary correction amount key_auto [0], and FIG. 5 shows the relationship between the exposure index and the temporary correction amount key_auto [1]. The defined one-dimensional LUT is shown. FIG. 6 shows the one-dimensional LUT in which the relationship between the skin color average luminance and the temporary correction amount key_auto [2] is defined. FIG. 7 shows the skin color average luminance or the overall average luminance and the temporary correction amount. Indicates a one-dimensional LUT that defines the relationship with key_auto [3].

  In the first to third embodiments, the brightness analysis values calculated by the image analysis unit 73 are skin color average brightness and overall average brightness (that is, n = 2). In the first embodiment, two temporary correction amounts (key_auto [2], corresponding to the flesh color average luminance and the overall average luminance calculated by the image analysis unit 73 using the one-dimensional LUT shown in FIGS. key_auto [3]) is set. In the first embodiment, since the exposure index is not calculated, the overall average luminance is used on the horizontal axis in FIG.

  Based on the natural light index calculated by the index calculation unit 74, the mixing coefficient setting unit 102 sets n as a weighting coefficient to be multiplied by each of the n temporary correction amounts set by the temporary correction amount setting unit 101. Set. 8 to 11 show one-dimensional LUTs that define the relationship between the natural light index and the mixing coefficients wgt [0] to wgt [3]. When the temporary correction amount key_auto [i] is set in the temporary correction amount setting unit 101, the mixing coefficient setting unit 102 sets the mixing coefficient wgt [i] (i = 0 to 3). The temporary correction amount setting unit 101 sets the temporary correction amounts key_auto [2] and key_auto [3]. Therefore, the mixing coefficient setting unit 102 uses the one-dimensional LUT shown in FIGS. 10 and 11 to calculate the index. The mixing coefficients wgt [2] and wgt [3] corresponding to the natural light index calculated by the unit 74 are set.

  The one-dimensional LUTs of FIGS. 6 and 7 and the one-dimensional LUTs of FIGS. 10 and 11 used in the first embodiment are stored in a memory (not shown).

Based on the temporary correction amount set by the temporary correction amount setting unit 101 and the mixing coefficient set by the mixing coefficient setting unit 102, the brightness correction amount calculation unit 103 performs the brightness correction as shown in Expression (2). Calculate the amount.
Brightness correction amount = key_auto [2] x wgt [2] + key_auto [3] x wgt [3] (2)

Next, the operation in the first embodiment will be described.
With reference to the flowchart of FIG. 12, the brightness correction process performed in the image processing unit 7 of the first embodiment will be described.

  First, a process of calculating a natural light index that represents the degree of outdoor photographing with natural light of the captured image data is performed (step T1). Hereinafter, the index calculation process in step T1 will be described with reference to the flowchart of FIG. In the following, a process for calculating all of the natural light index (index 4), the luminance ratio index (index 5), and the exposure index (index 6) is shown. In the first embodiment, a process for calculating only the natural light index (index 4) is shown. It is good.

  First, an occupancy ratio calculation process is performed in which the captured image data is divided into predetermined image areas, and an occupancy ratio (first occupancy ratio, second occupancy ratio) indicating the ratio of each divided area to the entire captured image data is calculated. Performed (step S1). Details of the occupation rate calculation process will be described later with reference to FIGS.

  Next, a bias amount calculation process for calculating a bias amount indicating a bias of the gradation distribution of the photographed image data is performed (step S2). The bias amount calculation process in step S2 will be described later in detail with reference to FIG.

  Next, an index representing the size of the dynamic range of the captured image data is calculated based on the occupation ratio calculated in step S1 and a coefficient set in advance according to the imaging condition (step S3), and this index calculation process Ends. The index calculation method in step S3 will be described in detail later.

  Next, the first occupancy rate calculation process will be described in detail with reference to the flowchart of FIG.

  First, the RGB values of the photographed image data are converted into the HSV color system (step S10). FIG. 15 shows an example of a conversion program (HSV conversion program) that obtains a hue value, a saturation value, and a lightness value by converting from RGB to the HSV color system using program code (c language). In the HSV conversion program shown in FIG. 15, the values of digital image data as input image data are defined as InR, InG, and InB, the calculated hue value is defined as OutH, the scale is defined as 0 to 360, and the saturation The value is OutS, the brightness value is OutV, and the unit is defined as 0 to 255.

  Next, the photographed image data is divided into regions composed of combinations of predetermined brightness and hue, and a two-dimensional histogram is created by calculating the cumulative number of pixels for each divided region (step S11). Hereinafter, the area division of the captured image data will be described in detail.

The lightness value (V) is 0-25 (v1), 26-50 (v2), 51-84 (v3), 85-169 (v4), 170-199 (v5), 200-224 (v6) , 225 to 255 (v7). Hue (H) is a skin hue hue area (H1 and H2) with a hue value of 0 to 39, 330 to 359, a green hue area (H3) with a hue value of 40 to 160, and a blue hue area with a hue value of 161 to 250 It is divided into four areas (H4) and a red hue area (H5). Note that the red hue region (H5) is not used in the following calculation because it is known that the contribution to the determination of the imaging condition is small. The flesh-color hue area is further divided into a flesh-color area (H1) and other areas (H2). Hereinafter, among the flesh-colored hue regions (H = 0 to 39, 330 to 359), the hue '(H) that satisfies the following formula (3) is defined as the flesh-colored region (H1), and the region that does not satisfy the formula (3) is ( H2).
10 <Saturation (S) <175,
Hue '(H) = Hue (H) + 60 (when 0 ≤ Hue (H) <300),
Hue '(H) = Hue (H)-300 (when 300 ≤ Hue (H) <360),
Luminance (Y) = InR x 0.30 + InG x 0.59 + InB x 0.11 (A)
As
Hue '(H) / Luminance (Y) <3.0 × (Saturation (S) / 255) +0.7 (3)
Therefore, the number of divided areas of the captured image data is 4 × 7 = 28. In addition, it is also possible to use the brightness (V) in the formula (3).

When the two-dimensional histogram is created, a first occupancy ratio indicating the ratio of the cumulative number of pixels calculated for each divided region to the total number of pixels (the entire captured image) is calculated (step S12), and the main occupancy ratio calculation is performed. The process ends. Assuming that the first occupancy ratio calculated in the divided area composed of the combination of the lightness area vi and the hue area Hj is Rij, the first occupancy ratio in each divided area is expressed as shown in Table 1.

Next, a method for calculating the index 1 and the index 2 will be described.
Table 2 shows the first coefficient required for calculating the index 1 that quantitatively indicates the accuracy of strobe shooting, that is, the lightness state of the face area at the time of strobe shooting, for each divided region. The coefficient of each divided area shown in Table 2 is a weighting coefficient by which the first occupancy rate Rij of each divided area shown in Table 1 is multiplied, and is set in advance according to the shooting conditions.

  FIG. 16 shows a lightness (v) -hue (H) plane. According to Table 2, a positive (+) coefficient is used for the first occupancy calculated from the region (r1) distributed in the skin color hue region of high brightness in FIG. 16, and blue other than that is blue. A negative (−) coefficient is used for the first occupancy calculated from the hue region (r2). FIG. 18 shows a first coefficient in the skin color area (H1) and a first coefficient in the other area (green hue area (H3)) as a curve (coefficient curve) that continuously changes over the entire brightness. It is shown. According to Table 2 and FIG. 18, in the region of high brightness (V = 170 to 224), the sign of the first coefficient in the skin color region (H1) is positive (+), and other regions (for example, the green hue region) The sign of the first coefficient in (H3)) is negative (-), and it can be seen that the signs of the two are different.

従って、H1〜H4領域の和は、下記の式(4-1)〜式(4-4)のように表される。
H1領域の和＝R11×(-44.0)＋R21×(-16.0)＋（中略）...＋R71×(-11.3) …(4-1)；
H2領域の和＝R12×0.0＋R22×8.6＋（中略）... ＋R72×(-11.1) …(4-2)；
H3領域の和＝R13×0.0＋R23×(-6.3)＋（中略）...＋R73×(-10.0) …(4-3)；
H4領域の和＝R14×0.0＋R24×(-1.8)＋（中略）...＋R74×(-14.6) …(4-4)． When the first coefficient in the lightness region vi and the hue region Hj is Cij, the sum of the Hk regions for calculating the index 1 is defined as in Expression (4).

Therefore, the sum of the H1 to H4 regions is expressed by the following formulas (4-1) to (4-4).
H1 area sum = R11 x (-44.0) + R21 x (-16.0) + (omitted) ... + R71 x (-11.3) ... (4-1);
Sum of H2 regions = R12 x 0.0 + R22 x 8.6 + (omitted) ... + R72 x (-11.1) ... (4-2);
H3 region sum = R13 x 0.0 + R23 x (-6.3) + (omitted) ... + R73 x (-10.0) ... (4-3);
Sum of H4 region = R14 x 0.0 + R24 x (-1.8) + (omitted) ... + R74 x (-14.6) ... (4-4).

The index 1 is defined as in Expression (5) using the sum of the H1 to H4 regions shown in Expressions (4-1) to (4-4).
Index 1 = sum of H1 region + sum of H2 region + sum of H3 region + sum of H4 region + 4.424 (5)

Table 3 shows, for each divided region, the second coefficient necessary for calculating the index 2 that quantitatively indicates the accuracy as backlight photographing, that is, the brightness state of the face region at the time of backlight photographing. The coefficient of each divided area shown in Table 3 is a weighting coefficient by which the first occupancy rate Rij of each divided area shown in Table 1 is multiplied, and is set in advance according to the shooting conditions.

  FIG. 17 shows a lightness (v) -hue (H) plane. According to Table 3, a negative (-) coefficient is used for the occupancy calculated from the region (r4) distributed in the intermediate lightness of the flesh color hue region in FIG. 17, and the low lightness (shadow) region ( A positive (+) coefficient is used for the occupation ratio calculated from r3). FIG. 19 shows the second coefficient in the skin color region (H1) as a curve (coefficient curve) that continuously changes over the entire brightness. According to Table 3 and FIG. 19, the sign of the second coefficient of the intermediate lightness region of the flesh color hue region having the lightness value of 85 to 169 (v4) is negative (−), and the lightness value is 26 to 84 (v2, It can be seen that the sign of the second coefficient in the low brightness (shadow) region of v3) is positive (+), and the sign of the coefficient in both regions is different.

従って、H1〜H4領域の和は、下記の式(6-1)〜式(6-4)のように表される。
H1領域の和＝R11×(-27.0)＋R21×4.5＋（中略）...＋R71×(-24.0) …(6-1)；
H2領域の和＝R12×0.0＋R22×4.7＋（中略）... ＋R72×(-8.5) …(6-2)；
H3領域の和＝R13×0.0＋R23×0.0＋（中略）...＋R73×0.0 …(6-3)；
H4領域の和＝R14×0.0＋R24×(-5.1)＋（中略）...＋R74×7.2 …(6-4)． When the second coefficient in the lightness area vi and the hue area Hj is Dij, the sum of the Hk areas for calculating the index 2 is defined as in Expression (6).

Therefore, the sum of the H1 to H4 regions is expressed by the following formulas (6-1) to (6-4).
H1 area sum = R11 x (-27.0) + R21 x 4.5 + (omitted) ... + R71 x (-24.0) ... (6-1);
Sum of H2 area = R12 x 0.0 + R22 x 4.7 + (omitted) ... + R72 x (-8.5) (6-2);
Sum of H3 area = R13 x 0.0 + R23 x 0.0 + (omitted) ... + R73 x 0.0 (6-3);
Sum of H4 area = R14 x 0.0 + R24 x (-5.1) + (omitted) ... + R74 x 7.2 (6-4).

The index 2 is defined as in Expression (7) using the sum of the H1 to H4 regions shown in Expressions (6-1) to (6-4).
Index 2 = sum of H1 area + sum of H2 area + sum of H3 area + sum of H4 area + 1.554 (7)
Since the index 1 and the index 2 are calculated based on the brightness of the captured image data and the distribution amount of the hue, it is effective for determining the imaging condition when the captured image data is a color image.

  Next, the second occupancy rate calculation process executed to calculate the index 3 will be described in detail with reference to the flowchart of FIG.

  First, the RGB values of the photographed image data are converted into the HSV color system (step S20). Next, the photographed image data is divided into regions each composed of a combination of the distance from the outer edge of the photographed image screen and the brightness, and a two-dimensional histogram is created by calculating the cumulative number of pixels for each divided region (step S21). Hereinafter, the area division of the captured image data will be described in detail.

  FIGS. 21A to 21D show four regions n1 to n4 divided according to the distance from the outer edge of the screen of the captured image data. An area n1 shown in FIG. 21A is an outer frame, an area n2 shown in FIG. 21B is an area inside the outer frame, and an area n3 shown in FIG. An inner area, an area n4 shown in FIG. 21D, is an area at the center of the captured image screen. Further, the lightness is divided into seven regions v1 to v7 as described above. Therefore, when the captured image data is divided into regions composed of combinations of the distance from the outer edge of the captured image screen and the brightness, the number of divided regions is 4 × 7 = 28.

When the two-dimensional histogram is created, a second occupancy ratio indicating the ratio of the cumulative number of pixels calculated for each divided region to the total number of pixels (the entire captured image) is calculated (step S22), and the main occupancy ratio calculation is performed. The process ends. If the second occupancy calculated in the divided area composed of the combination of the brightness area vi and the screen area nj is Qij, the second occupancy in each divided area is expressed as shown in Table 4.

図２２は、画面領域ｎ１〜ｎ４における第３の係数を、明度全体に渡って連続的に変化する曲線（係数曲線）として示したものである。 Next, a method for calculating the index 3 will be described.
Table 5 shows the third coefficient necessary for calculating the index 3 for each divided region. The coefficient of each divided area shown in Table 5 is a weighting coefficient by which the second occupation ratio Qij of each divided area shown in Table 4 is multiplied, and is set in advance according to the shooting conditions.

FIG. 22 shows the third coefficient in the screen areas n1 to n4 as a curve (coefficient curve) that continuously changes over the entire brightness.

従って、n1〜n4領域の和は、下記の式(8-1)〜式(8-4)のように表される。
n1領域の和＝Q11×40.1＋Q21×37.0＋（中略）...＋Q71×22.0 …(8-1)；
n2領域の和＝Q12×(-14.8)＋Q22×(-10.5)＋（中略）...＋Q72×0.0 …(8-2)；
n3領域の和＝Q13×24.6＋Q23×12.1＋（中略）...＋Q73×10.1 …(8-3)；
n4領域の和＝Q14×1.5＋Q24×(-32.9)＋（中略）...＋Q74×(-52.2) …(8-4)． If the third coefficient in the brightness area vi and the screen area nj is Eij, the sum of the nk area (screen area nk) for calculating the index 3 is defined as in Expression (8).

Accordingly, the sum of the n1 to n4 regions is expressed by the following formulas (8-1) to (8-4).
n1 area sum = Q11 x 40.1 + Q21 x 37.0 + (omitted) ... + Q71 x 22.0 (8-1);
Sum of n2 areas = Q12 x (-14.8) + Q22 x (-10.5) + (omitted) ... + Q72 x 0.0 (8-2);
n3 area sum = Q13 x 24.6 + Q23 x 12.1 + (omitted) ... + Q73 x 10.1 (8-3);
Sum of n4 regions = Q14 x 1.5 + Q24 x (-32.9) + (omitted) ... + Q74 x (-52.2) ... (8-4).

The index 3 is defined as Expression (9) using the sum of the n1 to n4 regions shown in Expressions (8-1) to (8-4).
Index 3 = sum of n1 region + sum of n2 region + sum of n3 region + sum of n4 region−12.6201 (9)
Since the index 3 is calculated based on a compositional feature (distance from the outer edge of the screen of the captured image data) based on the distribution position of the brightness of the captured image data, the imaging condition of the monochrome image as well as the color image is determined. It is also effective.

  Next, the bias amount calculation processing (step S2 in FIG. 13) will be described with reference to the flowchart in FIG.

式（１０）では、撮影画像データの各画素について和をとる。式（１０）において、画素輝度値とは、撮影画像データの各画素の輝度であり、全体平均輝度とは、撮影画像データ全体の輝度の平均値である。また、全体画素数とは、撮影画像データ全体の画素数である。 First, the luminance Y (brightness) of each pixel is calculated from the RGB (Red, Green, Blue) values of the photographed image data using Equation (A), and the luminance standard deviation (x1) is calculated (step 1). S23). The standard deviation (x1) of luminance is expressed as shown in Equation (10).

In Expression (10), the sum is calculated for each pixel of the captured image data. In Expression (10), the pixel luminance value is the luminance of each pixel of the captured image data, and the overall average luminance is the average value of the luminance of the entire captured image data. The total number of pixels is the number of pixels of the entire captured image data.

Next, as shown in Expression (11), a luminance difference value (x2) is calculated (step S24).
Luminance difference value (x2) = (maximum luminance value−total average luminance) / 255 (11)
In equation (11), the maximum luminance value is the maximum luminance value of the captured image data.

  Next, the average luminance value (x3) of the skin color area in the center of the screen of the captured image data is calculated (step S25), and further, the average luminance value (x4) in the center of the screen is calculated (step S26). Here, the center of the screen is, for example, an area configured by an area n3 and an area n4 in FIG.

Next, the flesh color luminance distribution value (x5) is calculated (step S27), and this deviation amount calculation processing is completed. When the maximum luminance value of the skin color area of the photographed image data is Yskin_max, the minimum luminance value of the skin color area is Yskin_min, and the average luminance value (skin color average luminance) of the skin color area is Yskin_ave, the skin color luminance distribution value (x5) is expressed by the equation (12). ).
x5 = (Yskin_max−Yskin_min) / 2−Yskin_ave (12)

Let x6 be the average luminance value of the skin color area in the center of the screen of the captured image data. The screen center here is, for example, an area composed of the area n2, the area n3, and the area n4 in FIG. At this time, the index 4 is defined as in Expression (13) using the index 1, index 3, and x6, and the index 5 is defined as in Expression (14) using the index 2, index 3, and x6. The
Index 4 = 0.46 × Index 1 + 0.61 × Index 3 + 0.01 × x6−0.79 (13)
Index 5 = 0.58 x Index 2 + 0.18 x Index 3 + (-0.03) x x6 + 3.34 (14)
Here, the weighting coefficient multiplied by each index in Expression (13) and Expression (14) is set in advance according to the shooting conditions.

指標６は、式（１５）のように表される。
指標６＝x1×0.02＋x2×1.13＋x3×0.06＋x4×(-0.01)＋x5×0.03−6.49 …（１５）
この指標６は、撮影画像データの画面の構図的な特徴だけでなく、輝度ヒストグラム分布情報を持ち合わせており、特に、ストロボ撮影シーンとアンダー撮影シーンの判別に有効である。 The index 6 is obtained by multiplying the deviation amounts (x1) to (x5) calculated in the deviation amount calculation process by a fourth coefficient set in advance according to the shooting conditions. Table 6 shows a fourth coefficient which is a weighting coefficient by which each deviation amount is multiplied.

The index 6 is expressed as in Expression (15).
Index 6 = x1 x 0.02 + x2 x 1.13 + x3 x 0.06 + x4 x (-0.01) + x5 x 0.03-6.49 (15)
This index 6 has not only the compositional characteristics of the screen of the photographed image data but also the luminance histogram distribution information, and is particularly effective for discriminating between the flash photography scene and the under photography scene.

  The index 4 shown in Expression (13) corresponds to a natural light index, the index 5 shown in Expression (14) corresponds to a luminance ratio index, and the index 6 shown in Expression (15) corresponds to an exposure index.

  Returning to FIG. When the index calculation process ends, the image analysis unit 73 calculates n brightness analysis values of the captured image data (step T2). In step T2, two brightness analysis values (skin color average brightness, overall average brightness) are calculated. Next, n (n = 2) values are extracted from the one-dimensional LUTs of FIGS. 6 and 7 by extracting values corresponding to the brightness analysis values (skin color average luminance, overall average luminance) calculated in step T2. Temporary correction amounts key_auto [2] and key_auto [3] are set (step T3).

  Next, by extracting a value corresponding to the natural light index calculated in step T1 from the one-dimensional LUTs of FIGS. 10 and 11, a mixing coefficient wgt [ 2], wgt [3] are set (step T4). Next, a brightness correction amount is calculated according to equation (2) (step T5), and the brightness for converting the captured image data based on the calculated brightness correction amount and the natural light index calculated in step T1. A correction curve is generated (step T6).

  24, 25, and 26, the brightness correction curves when −6.0 <natural light index ≦ −1.5, −1.5 <natural light index <2.0, and 2.0 ≦ natural light index <6.0 are calculated in step T5, respectively. It is shown for each brightness correction amount. 24 to 26, the brightness correction amount is represented as the number of correction buttons (−6, −4, −2, 0, +2, +4, +6 buttons) operated by the operation unit 12.

  When the brightness correction curve is generated, the brightness of the photographed image data is corrected according to the brightness correction curve (step T7), and the brightness correction process ends. The captured image data whose brightness has been corrected in this way is output to a designated output destination. Examples of the output destination include the display unit 13 and a printer connected to the imaging apparatus 100.

  As described above, according to the imaging apparatus 100 of the first embodiment, the temporary correction amount is set based on the brightness analysis value of the captured image data and the brightness reproduction target value, and the weight for multiplying the temporary correction amount is set. By setting a mixing coefficient as a coefficient based on the natural light index, and calculating a brightness correction amount based on the set temporary correction amount and the mixing coefficient, a main subject (e.g., a human face in a backlight scene or a strobe shooting scene) It is possible to obtain a brightness correction amount that can be reproduced with an optimal brightness in an output device (for example, a printer) that outputs captured image data.

  In addition, by generating a brightness correction curve based on the brightness correction amount and the natural light index calculated as described above, a scene with a large dynamic range of captured image data such as a backlight scene or a strobe shooting scene can be obtained. When outputting, the degree of deviation from the dynamic range of the output device becomes small, so the brightness of the main subject of the captured image data is properly finished, the bright and dark portions of the captured image data are crushed, and the high saturation color is saturated. It is possible to suppress crushing or a change in hue.

[Embodiment 2]
Next, Embodiment 2 of the present invention will be described.
Since the functions of the constituent elements common to the first to third embodiments have been described, functions unique to the second embodiment will be described below.

  FIG. 27 shows an internal configuration of the brightness correction amount calculation unit 75 according to the second embodiment, an index calculation unit 74, and a brightness correction curve generation unit 76. As shown in FIG. 27, the brightness correction amount calculation unit 75 of the second embodiment includes a temporary correction amount setting unit 110, a mixing coefficient setting unit 111, and a brightness correction amount calculation unit 112.

  The index calculation unit 74 according to the second embodiment calculates a natural light index (index 4) that represents the degree of outdoor shooting with natural light of the captured image data and a luminance ratio index (index 5) that represents the size of the dynamic range of the captured image data. . FIG. 28 shows a discrimination map for discriminating the shooting condition (shooting scene) of the shot image data based on the natural light index and the luminance ratio index.

  When n brightness analysis values are input from the image analysis unit 73, the temporary correction amount setting unit 110 sets n + 1 temporary correction amounts necessary to approximate each brightness analysis value to the reproduction target value. To do. The brightness analysis values calculated by the image analysis unit 73 are the skin color average brightness and the overall average brightness (that is, n = 2). Specifically, the temporary correction amount setting unit 110 uses the one-dimensional LUT shown in FIGS. 4, 6, and 7, and the skin color average luminance and overall average luminance calculated by the image analysis unit 73, and the index calculation unit Three temporary correction amounts (key_auto [0], key_auto [2], key_auto [3]) corresponding to the luminance ratio index calculated in 74 are set. In the second embodiment, since the exposure index is not calculated, the overall average luminance is used on the horizontal axis in FIG.

  Based on the natural light index calculated by the index calculation unit 74, the mixing coefficient setting unit 111 sets n + 1 as a weighting coefficient to be multiplied by each of the n + 1 temporary correction amounts set by the temporary correction amount setting unit 110. Set. In the temporary correction amount setting unit 110, the temporary correction amounts key_auto [0], key_auto [2], and key_auto [3] are set. Therefore, the mixing coefficient setting unit 111 is set to 1 shown in FIG. 8, FIG. 10, and FIG. Using the dimension LUT, the mixing coefficients wgt [0], wgt [2], and wgt [3] corresponding to the natural light index calculated by the index calculation unit 74 are set.

  The one-dimensional LUTs shown in FIGS. 4, 6, and 7 and the one-dimensional LUTs shown in FIGS. 8, 10, and 11 used in the second embodiment are stored in a memory (not shown).

Based on the temporary correction amount set by the temporary correction amount setting unit 110 and the mixing coefficient set by the mixing coefficient setting unit 111, the brightness correction amount calculation unit 112 performs the brightness correction as shown in Expression (16). Calculate the amount.
Brightness correction amount = key_auto [0] × wgt [0] + key_auto [2] × wgt [2] + key_auto [3] × wgt [3] (16)

  The brightness correction curve generation unit 76 determines the shooting condition (shooting scene, see FIG. 28) determined based on the natural light index and the luminance ratio index calculated by the index calculation unit 74, and the brightness calculated by the equation (16). A brightness correction curve is generated based on the height correction amount.

  FIG. 29A shows a brightness correction curve when the shooting condition is normal light according to the brightness correction amount, and FIG. 29B shows a brightness correction curve when the shooting condition is backlight. Shown by correction amount. FIG. 29 shows a brightness correction curve in a practical range (−6, −4, −2, 0 buttons) of the number of correction buttons operated by the operation unit 12.

Next, the operation in the second embodiment will be described.
The brightness correction process executed in the image processing unit 7 of the second embodiment will be described with reference to the flowchart of FIG.

  First, a natural light index (index 4 in Expression (13)) representing the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index (index 5 in Expression (14)) representing the size of the dynamic range of the captured image data. Processing to calculate is performed (step T10). Since the index calculation process in step T10 is the same as that shown in the first embodiment, a description thereof is omitted here. In the above-described index calculation process, the process of calculating all of the natural light index (index 4), the luminance ratio index (index 5), and the exposure index (index 6) has been described, but in the second embodiment, the natural light index (index 4) Further, only the luminance ratio index (index 5) may be calculated.

  When the index calculation process ends, the image analysis unit 73 calculates n brightness analysis values of the captured image data (step T11). In step T11, two brightness analysis values (skin color average brightness and overall average brightness) are calculated. Next, by extracting the brightness ratio index calculated in step T10 and the value corresponding to the brightness analysis value calculated in step T11 from the one-dimensional LUTs of FIGS. A temporary correction amount of n = 2) is set (step T12).

  Next, by extracting a value corresponding to the natural light index calculated in step T10 from the one-dimensional LUTs of FIGS. 8, 10, and 11, a mixture as a weighting coefficient to be multiplied to each of n + 1 temporary correction amounts. N + 1 coefficients are set (step T13). Next, the brightness correction amount is calculated by equation (16) (step T14). Next, the photographic image data is converted based on the shooting conditions (shooting scene) determined based on the natural light index and the luminance ratio index calculated in step T10 and the brightness correction amount calculated in step T14. A brightness correction curve (see FIG. 29) is generated (step T15).

  When the brightness correction curve is generated, the brightness of the captured image data is corrected according to the brightness correction curve (step T16), and the brightness correction process is terminated. The captured image data whose brightness has been corrected in this way is output to a designated output destination. Examples of the output destination include the display unit 13 and a printer connected to the imaging apparatus 100.

  As described above, according to the imaging apparatus 100 of the second embodiment, the temporary correction amount is set based on the brightness analysis value of the captured image data and the luminance ratio index, and the mixing is performed as the weighting coefficient by which the temporary correction amount is multiplied. The coefficient is set based on the natural light index, and the brightness correction amount is calculated based on the set temporary correction amount and the mixing coefficient, so that the brightness of the main subject (for example, a human face area) in a backlight scene or a flash photography scene is calculated. However, it is possible to improve the accuracy of obtaining a brightness correction amount that can be reproduced with an optimum brightness in an output device (for example, a printer) that outputs captured image data.

  Further, by generating a brightness correction curve based on the brightness correction amount calculated as described above and the shooting condition (shooting scene) determined based on the natural light index and the luminance ratio index, When outputting a scene with a large dynamic range of the captured image data, such as a flash shooting scene, the degree of deviation from the dynamic range of the output device is reduced, so the brightness of the main subject of the captured image data is appropriately finished and captured. It is possible to suppress with high accuracy that the bright and dark portions of the image data are crushed, the high-saturation color is saturated and crushed, and the hue is changed.

[Embodiment 3]
Next, a third embodiment of the present invention will be described.
Since the functions of the constituent elements common to the first to third embodiments have been described, functions unique to the third embodiment will be described below.

  The index calculation unit 74 according to the second embodiment includes a natural light index (index 4) that represents the degree of outdoor shooting with natural light in the captured image data, a luminance ratio index (index 5) that represents the size of the dynamic range of the captured image data, and shooting. An exposure index (index 6) representing under and over due to the exposure setting at the time is calculated.

  Hereinafter, specific examples of the internal configuration of the brightness correction amount calculation unit 75 according to the third embodiment will be described with reference to FIGS.

  FIG. 31 illustrates an internal configuration of the brightness correction amount calculation unit 75 according to Example 1 of the third embodiment. As illustrated in FIG. 31, the brightness correction amount calculation unit 75 according to the first embodiment includes a temporary correction amount setting unit 120, a mixing coefficient setting unit 121, a brightness correction amount calculation unit 122, a suppression coefficient calculation unit 123, and a multiplication unit 124. Consists of.

  When n brightness analysis values are input from the image analysis unit 73, the temporary correction amount calculation unit 120 sets n + 2 temporary correction amounts necessary to approximate each brightness analysis value to the reproduction target value. To do. The brightness analysis values calculated by the image analysis unit 73 are the skin color average brightness and the overall average brightness (that is, n = 2). Specifically, the temporary correction amount setting unit 120 uses the one-dimensional LUT shown in FIGS. 4 to 7 to calculate the flesh color average luminance and the overall average luminance calculated by the image analysis unit 73, and the index calculation unit 74. Four temporary correction amounts (key_auto [0] to key_auto [3]) corresponding to the luminance ratio index and the exposure index to be set are set.

  Based on the natural light index calculated by the index calculation unit 74, the mixing coefficient setting unit 121 sets n + 2 as a weighting coefficient for multiplying each of the n + 2 temporary correction amounts set by the temporary correction amount setting unit 120. Set. In the temporary correction amount setting unit 120, four temporary correction amounts key_auto [0] to key_auto [3] are set. Therefore, the mixing coefficient setting unit 121 uses the one-dimensional LUT shown in FIGS. The four mixing coefficients wgt [0] to wgt [3] corresponding to the natural light index calculated by the index calculation unit 74 are set.

  Note that the one-dimensional LUTs of FIGS. 4 to 7 and the one-dimensional LUTs of FIGS. 8 to 11 used in the third embodiment are stored in a memory (not shown).

Based on the temporary correction amount set by the temporary correction amount setting unit 120 and the mixing coefficient set by the mixing coefficient setting unit 121, the brightness correction amount calculation unit 122 performs the brightness correction as shown in Expression (17). The amount is calculated, and the calculation result is output to the multiplication unit 124.
Brightness correction amount = key_auto [0] × wgt [0] + key_auto [1] × wgt [1] + key_auto [2] × wgt [2] + key_auto [3] × wgt [3] (17)

  The suppression coefficient calculation unit 123 calculates the number of high-saturation pixels having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold, and the total number of pixels of the captured image data A suppression coefficient Re (0.0 <Re ≦ 1.0) for suppressing the brightness correction amount of the captured image data is calculated based on the ratio of the number of pixels of the high saturation with respect to. A method of calculating the suppression coefficient Re will be described in detail later with reference to FIG.

As shown in the equation (18), the multiplication unit 124 multiplies the brightness correction amount calculated by the brightness correction amount calculation unit 122 by the suppression coefficient Re calculated by the suppression coefficient calculation unit 123 to obtain a new value. A new brightness correction amount is calculated, and this new brightness correction amount is output to the brightness correction curve generation unit 76.
New brightness correction amount = Re × Brightness correction amount = Re × {key_auto [0] × wgt [0] + key_auto [1] × wgt [1] + key_auto [2] × wgt [2] + key_auto [3] × wgt [3]} (18)

  In the first embodiment, the brightness correction curve generation unit 76 includes a shooting condition (shooting scene) (see FIG. 28) determined based on the natural light index and the luminance ratio index calculated by the index calculation unit 74, and a multiplication unit 124. A brightness correction curve for converting photographed image data is generated based on the new brightness correction amount input from.

  FIG. 32 illustrates an internal configuration of the brightness correction amount calculation unit 75 according to Example 2 of the third embodiment. As shown in FIG. 32, the brightness correction amount calculation unit 75 according to the second embodiment includes a temporary correction amount setting unit 130, a mixing coefficient setting unit 131, a suppression coefficient calculation unit 132, and a brightness correction amount calculation unit 133. . Since the function of the suppression coefficient calculation unit 132 is the same as that of the suppression coefficient calculation unit 123 of the first embodiment, the description thereof is omitted here.

  When n brightness analysis values are input from the image analysis unit 73, the temporary correction amount calculation unit 130 sets n + 2 temporary correction amounts necessary to approximate each brightness analysis value to the reproduction target value. To do. The brightness analysis values calculated by the image analysis unit 73 are the skin color average brightness and the overall average brightness (that is, n = 2). The temporary correction amount setting unit 130 includes a multiplication unit 130a. The temporary correction amount setting unit 130 uses the one-dimensional LUT shown in FIGS. 4 to 7 and the skin color average luminance and the overall average luminance calculated by the image analysis unit 73 and the luminance ratio calculated by the index calculation unit 74. Four temporary correction amounts (key_auto [0] to key_auto [3]) corresponding to the index and the exposure index are extracted, and the suppression coefficient calculation unit 132 calculates these four temporary correction amounts by the multiplication unit 130a. The four temporary correction amounts Re × key_auto [0], Re × key_auto [1], Re × key_auto [2], and Re × key_auto [3] multiplied by the suppression coefficient Re are multiplied by “ It is set as “a new temporary correction amount”.

  Based on the natural light index calculated by the index calculation unit 74, the mixing coefficient setting unit 131 mixes the n + 2 new temporary correction amounts set by the temporary correction amount setting unit 130 as weighting factors. N + 2 are set. In the temporary correction amount setting unit 130, four new temporary correction amounts Re × key_auto [0] to key_auto [3] are set. Therefore, the mixing coefficient setting unit 121 performs the one-dimensional operation illustrated in FIGS. Using the LUT, four mixing coefficients wgt [0] to wgt [3] corresponding to the natural light index calculated by the index calculation unit 74 are set.

Based on the new temporary correction amount set by the temporary correction amount setting unit 130 and the mixing coefficient set by the mixing coefficient setting unit 131, the brightness correction amount calculation unit 133 determines the brightness as shown in Expression (19). The height correction amount is calculated, and the calculation result is output to the brightness correction curve generation unit 76.
Brightness correction amount = Re × {key_auto [0] × wgt [0] + key_auto [1] × wgt [1] + key_auto [2] × wgt [2] + key_auto [3] × wgt [3]} (19)

  In the second embodiment, the brightness correction curve generation unit 76 captures an imaging condition (imaging scene) (see FIG. 28) determined based on the natural light index and the luminance ratio index calculated by the index calculation unit 74, and an equation (19). ) To generate a brightness correction curve for converting the captured image data.

  FIG. 33 illustrates an internal configuration of the brightness correction amount calculation unit 75 according to Example 3 of the third embodiment. As shown in FIG. 33, the brightness correction amount calculation unit 75 of the third embodiment includes a temporary correction amount setting unit 140, a mixing coefficient setting unit 141, a suppression coefficient calculation unit 142, and a brightness correction amount calculation unit 143. . Since the function of the temporary correction amount calculation unit 140 is the same as that of the temporary correction amount setting unit 120 of the first embodiment, the description here will be described. Further, since the function of the suppression coefficient calculation unit 142 is the same as that of the suppression coefficient calculation unit 123 of the first embodiment and the suppression coefficient calculation unit 132 of the second embodiment, description thereof is omitted here.

  The mixing coefficient setting unit 141 is based on the natural light index calculated by the index calculation unit 74, and is a mixing coefficient as a weighting coefficient that is multiplied by each of the n + 2 new temporary correction amounts set by the temporary correction amount setting unit 140. N + 2 are set. The mixing coefficient setting unit 141 includes a multiplication unit 141a. The mixing coefficient setting unit 141 uses the one-dimensional LUT shown in FIGS. 8 to 11 to obtain four mixing coefficients wgt [0] to wgt [3] corresponding to the natural light index calculated by the index calculation unit 74. The four mixing coefficients Re × wgt [0] are extracted and multiplied by the suppression coefficient Re calculated by the suppression coefficient calculation unit 142 by the multiplication unit 141a and multiplied by the suppression coefficient Re. , Re × wgt [1], Re × wgt [2], and Re × wgt [3] are set as “new mixing coefficients”.

  The brightness correction amount calculation unit 143 calculates the brightness correction amount based on the temporary correction amount set by the temporary correction amount setting unit 140 and the new mixing coefficient set by the mixing coefficient setting unit 141, and the calculation result Is output to the brightness correction curve generator 76. The formula for calculating the brightness correction amount calculated by the brightness correction amount calculation unit 143 is the same as the equation (19).

  The brightness correction curve generation unit 76 shoots the shooting conditions (shooting scene) (see FIG. 28) determined based on the natural light index and the brightness ratio index calculated by the index calculation unit 74, and the brightness correction of Expression (19). Based on the amount, a brightness correction curve for converting the captured image data is generated.

Next, the operation in the third embodiment will be described.
With reference to the flowchart of FIG. 34, the brightness correction process performed in the image processing unit 7 of Embodiment 3 will be described. In FIG. 34, a process when the brightness correction amount calculation unit 75 of the first embodiment is applied will be described.

  First, a natural light index (indicator 4 in Expression (13)) representing the degree of outdoor photographing by natural light in the captured image data, and a luminance ratio index (indicator 5 in Expression (14)) representing the dynamic range of the captured image data, Then, a process of calculating an exposure index (index 6 in Expression (15)) representing under and over due to the exposure setting at the time of photographing is performed (step T20). Since the index calculation process in step T20 is the same as that shown in the first embodiment, a description thereof is omitted here.

  When the index calculation process ends, the image analysis unit 73 calculates n brightness analysis values of the captured image data (step T21). In step T21, two brightness analysis values (skin color average brightness and overall average brightness) are calculated. Next, n + 2 (n + 2) values are extracted from the one-dimensional LUTs of FIGS. 4 to 7 by extracting values corresponding to the luminance ratio index, the exposure index calculated in step T20, and the brightness analysis value calculated in step T21. A temporary correction amount of n = 2) is set (step T22).

  Next, it is determined whether or not the luminance ratio index calculated in step T20 is greater than a threshold value Th1 (step T23). Here, the threshold Th1 = 1.5. If it is determined in step T23 that the luminance ratio index> Th1 (step T23; YES), the hue condition of the pixel to be counted later as a high saturation pixel is set according to the natural light index calculated in step T20. (Step T24).

  FIG. 35 shows the hue condition (hue range) set according to the value of the natural light index in step T24. As shown in FIG. 35, the hue conditions are: hue H = 161 to 250 when −6.0 <natural light index ≦ −1.5, and hue H = 0 to 39, 161 to when −1.5 <natural light index <2.0. 250, 330-359, and when 2.0 ≦ natural light index <6.0, hue H = 0-39, 330-359.

When the hue condition is set, the number of pixels having the hue condition set in step T24 and having a saturation (S) greater than the threshold Th2 among the total number of pixels of the captured image data is calculated. The saturation level is set by the ratio (%) of the high saturation pixel number satisfying (S)> Th2 to the total pixel number (step T25). Here, Th2 = 130 (HSV color system, maximum value 255). Table 7 shows the ratio (%) of the high saturation pixel number satisfying saturation (S)> Th2 to the total pixel number and the suppression coefficient for each saturation level (saturation 1-4).

  When the saturation level is set, the suppression coefficient corresponding to the set saturation level is set according to Table 7 (step T26). Note that the processing of steps T23 to T26 is executed by the suppression coefficient calculation unit 123.

  If it is determined in step T23 that the luminance ratio index ≦ Th1 (step T23; NO), or if a suppression coefficient is calculated in step T26, each of the n + 2 temporary correction amounts set in step T22 is calculated. N + 2 mixing coefficients to be multiplied are set (step T27).

  Next, the brightness correction amount of the captured image data is calculated based on the temporary correction amount set in step T22 and the mixing coefficient set in step T27 (step T28). Here, when the suppression coefficient is calculated in step T26, in step T28, the “new brightness correction amount” shown in Expression (18) is set, and when the suppression coefficient is not calculated, in step T28, the expression is calculated. The “brightness correction amount” shown in (17) is set. Note that the value of “new brightness correction amount” or “brightness correction amount” calculated in step T 28 corresponds to the number of correction buttons operated by the operation unit 12.

  Next, a brightness correction curve for converting photographed image data is generated based on the “new brightness correction amount” or “brightness correction amount” set in step T28 (step T29). When the brightness correction curve is generated, the brightness of the captured image data is corrected according to the brightness correction curve (step T30), and the brightness correction process is terminated. The captured image data whose brightness has been corrected in this way is output to a designated output destination. Examples of the output destination include the display unit 13 and a printer connected to the imaging apparatus 100.

  As described above, according to the imaging apparatus 100 of the third embodiment, as illustrated in Examples 1 to 3, the suppression coefficient calculated based on the ratio of the high saturation pixel number to the total pixel number of the captured image data is used. Thus, by suppressing the brightness correction amount of the captured image data, it is possible to prevent saturation of the high saturation pixels in the captured image data having many high saturation pixels. In particular, the hue of a pixel to be counted as a high saturation pixel is determined based on the value of the natural light index, so that saturation of the high saturation pixel can be prevented with high accuracy.

  Note that the description in the present embodiment can be changed as appropriate without departing from the spirit of the present invention.

  For example, although the case where the brightness correction processing shown in each of the above embodiments is performed by an imaging apparatus such as a digital camera has been described, an image processing apparatus (a personal computer) installed in a minilab (small-scale development laboratory) may be used. 2) may be mounted with the image processing unit 7 of FIG.

  FIG. 36 shows a main configuration of an image processing apparatus 200 to which the present invention is applied. As shown in FIG. 36, the image processing apparatus 200 includes an image input unit 201, an image processing unit 202, and an image output unit 203.

  The image input unit 201 acquires photographed image data obtained by photographing a subject and outputs it to the image processing unit 202. The image output unit 203 includes a display such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube), and displays the captured image data processed by the image processing unit 202. Further, the image output unit 203 may include a printing unit that prints out the captured image data processed by the image processing unit 202.

  As shown in FIG. 36, the image processing unit 202 includes an image analysis unit 204, an index calculation unit 205, a brightness correction amount calculation unit 206, a brightness correction curve generation unit 207, and an image quality correction unit 208. Are equivalent to the image analysis unit 73, index calculation unit 74, brightness correction amount calculation unit 75, brightness correction curve generation unit 76, and image quality correction unit 72 of FIG.

  However, in the case of the image processing apparatus 200 installed in the minilab, the brightness correction curve has seven types (−6, −4, −2, 0, +2, +4, +6 buttons) shown in FIGS. In addition to the four types (−6, −4, −2, 0 buttons) shown in FIG. 29, it is possible to generate various types of brightness correction curves.

1 is a block diagram showing a main part configuration of an imaging apparatus according to an embodiment of the present invention. The block diagram which shows the internal structure of an image process part. The block diagram which shows the internal structure of the brightness correction amount calculation part in Embodiment 1 of this invention. LUT indicating the relationship between the luminance ratio index and the provisional correction amount key_auto [0]. LUT indicating the relationship between the exposure index and the temporary correction amount key_auto [1]. LUT indicating the relationship between the skin color average luminance and the provisional correction amount key_auto [2]. LUT indicating the relationship between the flesh color average luminance or the overall average luminance and the temporary correction amount key_auto [3]. LUT indicating the relationship between the natural light index and the mixing coefficient wgt [0]. LUT indicating the relationship between the natural light index and the mixing coefficient wgt [1]. LUT indicating the relationship between the natural light index and the mixing coefficient wgt [2]. LUT indicating the relationship between the natural light index and the mixing coefficient wgt [3]. 5 is a flowchart illustrating brightness correction processing executed in the image processing unit according to the first embodiment. The flowchart which shows an index calculation process. The flowchart which shows the 1st occupation rate calculation process which calculates the 1st occupation rate for every area | region of lightness and hue. The figure which shows an example of the program which converts from RGB to HSV color system. The figure which shows the brightness | luminance (V) -hue (H) plane, and the area | region r1 and the area | region r2 on a VH plane. The figure which shows the brightness | luminance (V) -hue (H) plane, and the area | region r3 and the area | region r4 on a VH plane. The figure which shows the curve showing the 1st coefficient by which the 1st occupation rate for calculating the parameter | index 1 is multiplied. The figure which shows the curve showing the 2nd coefficient by which the 1st occupation rate for calculating the parameter | index 2 is multiplied. The flowchart which shows the 2nd occupation rate calculation process which calculates a 2nd occupation rate based on the composition of picked-up image data. The figure which shows the area | regions n1-n4 determined according to the distance from the outer edge of the screen of picked-up image data. The figure which shows the curve showing the 3rd coefficient for multiplying the 2nd occupation rate for calculating the parameter | index 3 according to area | region (n1-n4). 7 is a flowchart showing a bias amount calculation process. The figure which shows the brightness correction curve in case of -6.0 <natural light index <=-1.5. The figure which shows the brightness correction curve in case of -1.5 <natural light parameter | index 2.0. The figure which shows the brightness correction curve in case of 2.0 <= natural light parameter | index <6.0. The block diagram which shows the internal structure of the brightness correction amount calculation part in Embodiment 2 of this invention. The figure which shows the discrimination | determination map for discriminating an imaging condition from a natural light parameter | index and a luminance ratio parameter | index. FIG. 5B is a diagram illustrating a brightness correction curve (a) when the shooting condition is a normal light and a brightness correction curve when the shooting condition is a backlight. 9 is a flowchart illustrating brightness correction processing executed in the image processing unit of the second embodiment. The block diagram which shows the internal structure of the brightness correction amount calculation part in Example 1 of Embodiment 3 of this invention. The block diagram which shows the internal structure of the brightness correction amount calculation part in Example 2 of Embodiment 3 of this invention. The block diagram which shows the internal structure of the brightness correction amount calculation part in Example 3 of Embodiment 3 of this invention. 10 is a flowchart illustrating brightness correction processing executed in the image processing unit according to the third embodiment. The figure which shows the relationship between a natural light parameter | index and the hue condition of a high saturation pixel. 1 is a block diagram showing a main part configuration of an image processing apparatus to which the present invention is applied.

Explanation of symbols

1 Lens 2 Aperture 3 CCD
4 Analog processing circuit 5 A / D converter 6 Temporary storage memory 7 Image processing unit 70 Pre-processing unit 71 Brightness correction unit 72 Image quality correction unit 73 Image analysis unit 74 Index calculation unit 75 Brightness correction amount calculation unit 76 Brightness correction Curve generation unit 8 Header information processing unit 9 Storage device 10 CCD drive circuit 11 Control unit 12 Operation unit 13 Display unit 14 Strobe drive circuit 15 Strobe 16 Focal length adjustment circuit 17 Automatic focus drive circuit 20 Motor 100 Imaging device 200 Image processing device 201 Image input unit 202 Image processing unit 203 Image output unit 204 Image analysis unit 205 Index calculation unit 206 Brightness correction amount calculation unit 207 Brightness correction curve generation unit 208 Image quality correction unit

Claims (24)

An imaging apparatus that captures captured image data by capturing a subject and performs processing for optimizing the brightness of a main subject in the captured image data,
Index calculating means for calculating a natural light index representing the degree of outdoor shooting by natural light of the captured image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generating means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculating means and the natural light index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An imaging apparatus comprising: An imaging apparatus that captures captured image data by capturing a subject and performs processing for optimizing the brightness of a main subject in the captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An imaging apparatus comprising: An imaging apparatus that captures captured image data by capturing a subject and performs processing for optimizing the brightness of a main subject in the captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation means by the suppression coefficient;
A correction curve generating means for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplying means, the natural light index and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An imaging apparatus comprising: An imaging apparatus that captures captured image data by capturing a subject and performs processing for optimizing the brightness of a main subject in the captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting means by the suppression coefficient;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of a plurality of new temporary correction amounts obtained by the multiplying means,
A correction amount calculating means for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of new temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An imaging apparatus comprising: An imaging apparatus that captures captured image data by capturing a subject and performs a process of optimizing the brightness of a main subject in the captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting means by the suppression coefficient;
Correction amount calculation means for calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An imaging apparatus comprising: The index calculating means includes
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. The imaging device according to claim 1, wherein the imaging device is calculated. An image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
Index calculating means for calculating a natural light index representing the degree of outdoor shooting by natural light of the captured image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generating means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculating means and the natural light index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An image processing apparatus comprising: An image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An image processing apparatus comprising: An image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
Correction amount calculating means for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation means by the suppression coefficient;
A correction curve generating means for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplying means, the natural light index and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An image processing apparatus comprising: An image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting means by the suppression coefficient;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of a plurality of new temporary correction amounts obtained by the multiplying means,
A correction amount calculating means for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting means and the plurality of new temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An image processing apparatus comprising: An image processing apparatus that performs processing for optimizing the brightness of a main subject in captured image data,
A natural light index that represents the degree of outdoor photographing by natural light of the photographed image data, and an index calculation unit that calculates a luminance ratio index that represents the size of the dynamic range of the photographed image data;
Temporary correction amount setting means for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculating means, a mixing coefficient setting means for setting a mixing coefficient as a weighting coefficient for multiplying each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculating means for calculating a suppression coefficient for
Multiplication means for calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting means by the suppression coefficient;
Correction amount calculation means for calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication means and the plurality of temporary correction amounts;
Correction curve generation means for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation means, the natural light index, and the luminance ratio index;
Correction means for correcting the brightness of the captured image data in accordance with the correction curve generated by the correction curve generation means;
An image processing apparatus comprising: The index calculating means includes
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. The image processing apparatus according to any one of claims 7 to 11, wherein the image processing device is calculated. An image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculating step for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data;
A temporary correction amount setting step of setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of temporary correction amounts;
A correction curve generating step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculating step and the natural light index;
A correction step of correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation step;
An image processing method comprising: An image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting step for setting a plurality of provisional correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of temporary correction amounts;
A correction curve generation step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation step;
An image processing method comprising: An image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting step for setting a plurality of provisional correction amounts for the photographed image data based on the brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation step for calculating a suppression coefficient for
A multiplication step of calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation step by the suppression coefficient;
A correction curve generating step for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplication step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation step;
An image processing method comprising: An image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A temporary correction amount setting step of setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation step for calculating a suppression coefficient for
A multiplication step of calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting step by the suppression coefficient;
Based on the natural light index calculated by the index calculation step, a mixing factor setting step for setting a mixing factor as a weighting factor to be multiplied to each of a plurality of new temporary correction amounts obtained by the multiplication step;
A correction amount calculating step of calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting step and the plurality of new temporary correction amounts;
A correction curve generation step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation step;
An image processing method comprising: An image processing method for performing processing for optimizing the brightness of a main subject in captured image data,
An index calculation step of calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A temporary correction amount setting step of setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation step, a mixing coefficient setting step for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation step for calculating a suppression coefficient for
A multiplication step of calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting step by the suppression coefficient;
A correction amount calculating step of calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication step and the plurality of temporary correction amounts;
A correction curve generation step for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation step, the natural light index, and the luminance ratio index;
A correction step of correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation step;
An image processing method comprising: In the index calculation step,
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. The image processing method according to claim 13, wherein the image processing method is calculated. On the computer,
An index calculation function for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data;
A temporary correction amount setting function for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating function for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function and the natural light index;
A correction function for correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation function;
An image processing program for realizing On the computer,
An index calculation function for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting function for setting a plurality of provisional correction amounts for the photographed image data based on a brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculation function for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function, the natural light index and the luminance ratio index;
A correction function for correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation function;
An image processing program for realizing On the computer,
An index calculation function for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A provisional correction amount setting function for setting a plurality of provisional correction amounts for the photographed image data based on a brightness analysis value of the photographed image data, the luminance ratio index, and a reproduction target value of brightness;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
A correction amount calculating function for calculating a brightness correction amount of the captured image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation function for calculating a suppression coefficient for
A multiplication function for calculating a new brightness correction amount by multiplying the brightness correction amount calculated by the correction amount calculation function by the suppression coefficient;
A correction curve generation function for generating a correction curve for converting the captured image data based on the new brightness correction amount obtained by the multiplication function, the natural light index, and the luminance ratio index;
A correction function for correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation function;
An image processing program for realizing On the computer,
An index calculation function for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A temporary correction amount setting function for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation function for calculating a suppression coefficient for
A multiplication function for calculating a new temporary correction amount by multiplying each of the plurality of temporary correction amounts set by the temporary correction amount setting function by the suppression coefficient;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient for multiplying each of a plurality of new temporary correction amounts obtained by the multiplication function;
A correction amount calculation function for calculating a brightness correction amount of the photographed image data based on the mixing coefficient set by the mixing coefficient setting function and the plurality of new temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function, the natural light index and the luminance ratio index;
A correction function for correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation function;
An image processing program for realizing On the computer,
An index calculation function for calculating a natural light index that represents the degree of outdoor shooting by natural light of the captured image data, and a luminance ratio index that represents the size of the dynamic range of the captured image data;
A temporary correction amount setting function for setting a plurality of temporary correction amounts for the captured image data based on a brightness analysis value of the captured image data and a brightness reproduction target value;
Based on the natural light index calculated by the index calculation function, a mixing coefficient setting function for setting a mixing coefficient as a weighting coefficient to be multiplied to each of the plurality of temporary correction amounts;
The brightness correction amount of the captured image data is suppressed based on the number of pixels of high saturation having a predetermined hue that is set based on the natural light index and the saturation of the captured image data is higher than a predetermined threshold. A suppression coefficient calculation function for calculating a suppression coefficient for
A multiplication function for calculating a new mixing coefficient by multiplying the mixing coefficient set by the mixing coefficient setting function by the suppression coefficient;
A correction amount calculation function for calculating a brightness correction amount of the captured image data based on the new mixing coefficient obtained by the multiplication function and the plurality of temporary correction amounts;
A correction curve generation function for generating a correction curve for converting the captured image data based on the brightness correction amount calculated by the correction amount calculation function, the natural light index and the luminance ratio index;
A correction function for correcting the brightness of the captured image data according to the correction curve generated by the correction curve generation function;
An image processing program for realizing When realizing the index calculation function,
A first calculation process that divides the captured image data into regions composed of combinations of predetermined brightness and hue, and calculates a first occupancy ratio that indicates a ratio of the entire captured image data for each of the divided regions; The captured image data is divided into a predetermined area composed of a combination of the distance from the outer edge of the screen of the captured image data and the brightness, and a second occupation indicating the ratio of the divided area to the entire captured image data Executing at least one of the second calculation processes for calculating the rate,
Calculating a deviation amount indicating a deviation in gradation distribution of the photographed image data;
The natural light index and / or the luminance ratio index are obtained by multiplying the calculated first occupancy ratio and / or second occupancy ratio and the deviation amount by a coefficient set in advance according to a shooting condition. The image processing program according to any one of claims 19 to 23, wherein:

Images