JP2000004351A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct image degradation that is caused by a lens characteristic with high accuracy to image data obtained by reading an image recorded on recording material. SOLUTION: When an image data that represents an image recorded on a photographic film with a film with lens is an object to be processed (316 is yes), the number of pixels x0 along an x-direction (film carrying direction) of the image data and the number of pixels y0 along a y-direction (film width direction) are operated and the pixel of a position that is from x0/2 in the x-direction and y0/2 in the y-direction from an image corner is extracted as a center position of the image (320 and 322). Correction data that corresponds to a lens kind of a film with lens which is used to photograph and record the image is fetched and the correction of the brightness drop in image margin, due to beam attenuation as lens pheriphery, image geometric distortion owing to lens distortion aberration and image color bleeding due to lens magnification chromatic aberration is performed on image data obtained by standardizing the coordinates of each pixel with the center position of the image as reference (324 to 334).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image processing apparatus, and more particularly to an image processing apparatus which uses image data of an image obtained by reading a recording material on which an image is projected and recorded through a lens, based on characteristics of the lens. The present invention relates to an image processing apparatus for correcting deterioration of the image quality of an image represented by the image data.

[0002]

2. Description of the Related Art Conventionally, after performing various image processing on image data obtained by reading a film image recorded on a photographic film or image data input from a digital camera or the like, printing is performed. 2. Description of the Related Art An image processing system capable of outputting an image in various output forms, such as recording an image on a recording material such as paper, displaying an image on a display means such as a display, and storing image data on an information recording medium, is known. Have been. According to this image processing system, the image quality of an output image can be freely controlled from the image processing system by performing image processing on image data, as compared with a conventional photographic processing system that records a film image on photographic paper by surface exposure. Higher output image quality can be realized.

Incidentally, since the lens of a film with a lens is generally formed of an inexpensive plastic lens, aberrations such as distortion and chromatic aberration of magnification are large. In addition, geometric distortion caused by lens distortion and color blur caused by chromatic aberration of magnification of the lens occur relatively remarkably. Also, the so-called peripheral dimming of the lens of the lens-equipped film is remarkable, and the brightness of the peripheral portion of the image of the film image exposed and recorded on the photographic film by the lens-equipped film is significantly reduced as compared with the central portion of the image. There is also a problem. For this reason, in the above-described image processing system, in order to obtain a high-quality output image from the above-described image, distortion correction for correcting geometric distortion of an image due to lens distortion, and lens magnification Consideration has been given to performing magnification chromatic aberration correction for correcting color fringing of an image due to chromatic aberration, or peripheral dimming correction for correcting a decrease in brightness at the periphery of an image due to peripheral dimming of a lens.

[0004] Distortion correction is performed, for example, by changing the direction and amount of movement of the position of each pixel caused by lens distortion with reference to the original position (grid point position) of each pixel constituting the film image. The distortion correction data to be represented is measured and stored in advance for each type of lens, and the distortion correction data corresponding to the type of lens used for shooting is fetched for the image data to be processed, and the fetched distortion correction is performed. The position of each pixel represented by the data of each pixel when there is no distortion is determined based on the data, and the density value at the original position (grid point position) is obtained by interpolation.

[0005] Further, magnification chromatic aberration correction is performed, for example, at each position on a film image, with respect to a non-reference color (for example, R, B) with respect to a reference color (for example, G) caused by the chromatic aberration of magnification of the lens.
The magnification chromatic aberration correction data representing the direction of color misregistration and the amount of color misregistration are measured and stored in advance for each type of lens, and the chromatic aberration of magnification corresponding to the type of lens used for shooting is compared with the image data to be processed. The correction data is fetched, the position of each pixel represented by the data of each pixel when there is no chromatic aberration of magnification is determined for each non-reference color based on the fetched chromatic aberration correction data, and the original position (the position of the pixel of the reference color and This is achieved by obtaining the density value of the non-reference color at the same position) by interpolation.

Further, in the vignetting correction, for example, vignetting correction data representing the amount of dimming light at each position on the film image is measured and stored in advance for each type of lens, and the image data to be processed is photographed. Ambient extinction correction data corresponding to the type of lens used for is taken, and the amount of change in density value caused by the extinction is determined for each pixel based on the acquired extinction extinction correction data. This is achieved by calculating the density value in the case where there is no pixel for each pixel.

[0007]

As described above, correction of image quality deterioration due to lens characteristics such as distortion correction, magnification chromatic aberration correction, and peripheral dimming correction requires a correction amount for each pixel. Correction is performed for each pixel. For this reason, it is necessary to accurately associate the data of each pixel constituting the image data with the correction amount for each pixel represented from each correction data, and if this association is incorrect, the data of each pixel is By performing the correction with a correction amount different from the correction amount assumed in advance, the geometric distortion of the image represented by the image data, color bleeding, the decrease in the brightness of the peripheral portion of the image is not eliminated, geometric distortion, Color bleeding and a decrease in brightness at the periphery of the image may be increased. However,
For image data obtained by reading an image, it is established what standard is used to associate the data of each pixel with the correction amount of each pixel so that the association can be performed accurately and easily. The fact was not done.

The present invention has been made in view of the above-mentioned facts, and highly accurately detects the deterioration of image quality due to the characteristics of a lens with respect to image data obtained by reading an image recorded on a recording material. It is an object to obtain an image processing device that can perform correction.

[0009]

A criterion for easily associating a plurality of types of data having a two-dimensional spread with each other is, for example, a corner if the outer edge of an image recorded on a recording material is rectangular. It is conceivable that one of the four sides constituting the outer edge of the image or the image is used as the criterion, and a plurality of types of data are associated with each other so that the criterion matches.
However, particularly with a simple camera (projection recording device) such as a film with a lens, the shape of the outer edge of an image recorded on a recording material such as a photographic film may be distorted. May not be able to accurately associate a plurality of types of data. The inventor of the present application has conducted experiments using various criteria as the reference of the association. As a result, if the center position of the image is used as the reference, the correction of the image quality deterioration caused by the characteristics of the lens for most of the images ( Pixel-by-pixel correction) is performed with high accuracy.

[0010] Based on the above, the image processing apparatus according to the first aspect of the present invention, based on the data obtained by reading a recording material on which an image is projected and recorded via a lens, the image processing apparatus on the recording material Determine the screen position of the image,
Calculating means for calculating the center position of the image based on the determined screen position; obtaining means for obtaining information relating to the characteristics of the lens; and information based on the information relating to the characteristics of the lens obtained by the obtaining means. With respect to the image data of the image, with respect to the center position of the image calculated by the calculation unit,
Correction means for correcting the deterioration of the image quality caused by the characteristics of the lens.

According to the first aspect of the present invention, the screen position of the image on the recording material is determined by the calculating means based on data obtained by reading the recording material on which the image is projected and recorded via the lens. Then, the center position of the image is calculated based on the determined screen position. The center position of the image can be obtained by a relatively simple calculation. For example, as described in claim 2, based on the determined screen position, approximately two of the four sides forming the outer edge of the screen are substantially aligned. Parallel first
Is located at the center of both ends along the first direction of the screen, and the positions along a second direction orthogonal to the first direction are both ends along the second direction of the screen. Can be calculated as the center position of the image.

[0012] The acquisition means acquires information relating to the characteristics of the lens used when the image is projected and recorded on the recording material. The information related to the characteristics of the lens may be information representing the characteristics of the lens itself, information representing a correction value for correcting image data according to the characteristics of the lens, or a lens. Or information indicating the type of device (such as a camera) that has projected and recorded an image on a recording material. When information indicating the type of lens or information indicating the type of the projection recording apparatus (the type of lens can be determined from this information) is acquired as information related to the characteristics of the lens, A correction value for correcting image data can be indirectly determined from the acquired information.

[0013] Then, the correction means, based on the information related to the characteristics of the lens acquired by the acquisition means, the image data of the image (data obtained by reading the recording material (judgment of the screen position / Data used for the calculation) or data obtained by reading the image again), with reference to the center position of the image calculated by the calculation means. The image quality degradation of the image represented by the image data due to the characteristics of the lens is corrected. The correction based on the center position of the image is specifically, for example, standardizing the coordinates of each pixel of the image data based on the center position of the image,
This can be performed by determining the correction amount for each pixel based on the coordinates of each pixel in the standardized image data, and performing correction in pixel units.

As described above, according to the first aspect of the present invention, the center position of the image is calculated, and the deterioration of the image quality due to the characteristics of the lens is corrected based on the calculated center position. With respect to the image data obtained by reading the image, it is possible to highly accurately correct the deterioration of the image quality due to the characteristics of the lens.

According to a third aspect of the present invention, in the first aspect of the present invention, the calculating means is configured to read the recording material preliminarily at a predetermined resolution to obtain a center of the image based on preliminary read data. The position is calculated, and the correction unit performs the correction on the main read data obtained by performing the main read for reading the recording material at a resolution higher than the predetermined resolution.

When the image content of the image projected and recorded on the recording material is indefinite or the like, in order to accurately read the recording material (image), the recording material is preliminarily read at a relatively low resolution and obtained by the preliminary reading. In many cases, the reading conditions at the time of the main reading are determined based on the obtained preliminary reading data, and the main reading for reading the recording material with relatively high resolution is performed in accordance with the determined reading conditions. As described above, in the case where the preliminary reading and the main reading are performed on the recording material, the center position of the image is calculated based on the preliminary reading data. The calculation of the position can be performed in a short time.

By the way, various methods have been conventionally proposed for determining the screen position. However, no matter which method is used, the screen position cannot be accurately determined (for example, a negative film may be overexposed under negative light). Etc.). Therefore, the invention according to claim 4 is the invention according to claim 1, wherein the display means for displaying an image includes:
Display control means for displaying the result of the screen position determination by the arithmetic means on the display means; and input means for inputting information for instructing correction of the result of the screen position determination displayed on the display means. The information processing means, when the information for instructing the correction of the screen position determination result is input via the input means, corrects the screen position determination result in accordance with the instruction, the corrected screen position The calculation of the center position is performed based on this.

According to the present invention, the result of the determination of the screen position by the calculation means is displayed on the display means, and when the information for instructing the correction of the result of the determination of the screen position is input through the input means, Since the screen position determination result is corrected according to the instruction and the center position is calculated based on the corrected screen position, even if the image screen position is erroneously determined, the image quality deterioration due to the characteristics of the lens may be reduced. It is possible to prevent the correction accuracy from lowering.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings. First, a digital lab system according to the present embodiment, including the image processing apparatus according to the present invention, will be described.

(Schematic Configuration of Entire System) FIG. 1 shows a schematic configuration of a digital laboratory system 10 according to the present embodiment, and FIG. 2 shows an appearance of the digital laboratory system 10. As shown in FIG. 1, the lab system 10 includes a line CCD scanner 14, an image processing unit 16 as an image processing device according to the present invention, a laser printer unit 18, and a processor unit 20. The CCD scanner 14 and the image processing unit 16 are integrated as an input unit 26 shown in FIG. 2, and the laser printer unit 18 and the processor unit 20 are integrated as an output unit 28 shown in FIG.

The line CCD scanner 14 is for reading a film image (a negative image or a positive image visualized by subjecting a subject to image processing and development processing) recorded on a photographic film such as a negative film or a reversal film. , For example, 135 size photographic film,
Film images of a 110-size photographic film, a photographic film on which a transparent magnetic layer is formed (240-size photographic film: so-called APS film), and 120- and 220-size (Broni-size) photographic films are to be read. Can be. Line CCD scanner 14
Indicates that the film image to be read is a three-line color C
It reads on a CD and outputs R, G, B image data.

As shown in FIG. 2, the line CCD scanner 14 is mounted on a work table 30. The image processing section 16 is stored in a storage section 32 formed below the work table 30, and an opening / closing door 34 is attached to an opening of the storage section 32. Normally, the inside of the storage unit 32 is concealed by the open / close door 34, and when the open / close door 34 is rotated, the inside is exposed, and the image processing unit 16 can be taken out.

The work table 30 has a display 164 mounted on the back side and two types of keyboards 166A and 166B. One keyboard 166 </ b> A is embedded in the work table 30. The other keyboard 166B is housed in the drawer 36 of the work table 30 when not in use, and is taken out of the drawer 36 when used and is arranged on the keyboard 166A. When the keyboard 166B is used, a connector (not shown) attached to the tip of a cord (signal line) extending from the keyboard 166B,
The keyboard 166 </ b> B is electrically connected to the image processing unit 16 via the jack 37 by being connected to the jack 37 provided on the work table 30.

A mouse 40 is arranged on the work surface 30U of the work table 30. The mouse 40 has a code (signal line) extending through the hole 42 provided in the work table 30 into the storage unit 32.
Is connected to The mouse 40 is stored in the mouse holder 40A when not in use, and is taken out of the mouse holder 40A when in use and placed on the work surface 30U.

The image processing section 16 receives image data (scan data) output from the line CCD scanner 14 and obtains image data obtained by photographing with a digital camera and a document other than a film image (for example, a reflection document). ) Is input from outside (e.g., via a storage medium such as a memory card). Input from another information processing device via a communication line, etc.).

The image processing section 16 performs image processing such as various corrections on the input image data, and outputs the image data to the laser printer section 18 as recording image data. Also,
The image processing unit 16 outputs image data on which image processing has been performed to an external device as an image file (for example, outputs the image data to a storage medium such as a memory card, or transmits the image data to another information processing device via a communication line). It is also possible.

The laser printer unit 18 includes R, G, and B laser light sources, and irradiates a photographic paper with laser light modulated in accordance with recording image data input from the image processing unit 16 to perform scanning exposure. To record an image on photographic paper. Further, the processor unit 20 performs each process of color development, bleach-fix, washing, and drying on the photographic paper on which the image is recorded by the scanning exposure by the laser printer unit 18. Thus, an image is formed on the printing paper.

(Configuration of Image Processing Unit) Next, the image processing unit 16
Will be described with reference to FIG. Image processing unit 1
6 is R input from the line CCD scanner 14,
The line scanner correction unit 122 corresponding to the G and B data
R, 122G, and 122B are provided. The line scanner correction units 122R, 122G, and 122B have the same configuration, and are hereinafter generically referred to as “line scanner correction unit 122” without distinction.

The line scanner correction unit 122 outputs the line C
Line CC by CD reading photographic film
When scan data is input from the D-scanner 14, dark correction for reducing the dark output level of a cell corresponding to each pixel from the input scan data, and data obtained by performing the dark correction are logarithmically converted to data representing the density of a photographic film. Density conversion for conversion, shading correction for correcting the data subjected to the density conversion in pixel units according to the unevenness in the amount of light illuminating the photographic film, and accurately corresponds to the amount of incident light in the data subjected to the shading correction The processing of the defective pixel correction which is newly generated by interpolating the data of the cell (so-called defective pixel) to which the output signal is not output from the data of the surrounding pixels is sequentially performed.

The output terminal of the line scanner correction unit 122 is connected to the input terminal of the selector 132, and the data subjected to each of the above-described processes in the line scanner correction unit 122 is input to the selector 132 as scan data. Also,
The input end of the selector 132 is also connected to the data output end of the input / output controller 134, from which file image data input from the outside is input to the selector 132. The output terminal of the selector 132 is connected to the input / output controller 134 and the data input terminals of the image processors 136A and 136B. The selector 132 converts the input image data into an input / output controller 134 and an image processor 136.
A and 136B can be selectively output.

The image processor unit 136A includes a memory controller 138, an image processor 140, and three frame memories 142A, 142B, 142C. Frame memories 142A, 142B, 142C
Have a capacity capable of storing image data of one or more frames of film images, and the image data input from the selector 132 is stored in one of the three frame memories 142 by the memory controller 138. You.

The image processor 14 according to the present embodiment
4, the LF aberration correction unit 140A and the other image processing unit 140B are sequentially connected as shown in FIG. 4, and are stored in a frame memory 142 (denoted as a fine scan memory 142 in FIG. 4). The image data is fetched, and various image processing is performed according to processing conditions determined for each image by an auto setup engine 144 (described later).

The LF aberration correction section 140A is activated when the image data to be processed is image data representing a film image photographed and recorded on a photographic film by a film with a lens (also referred to as LF). Various correction processes to correct the image quality deterioration caused by the characteristics of the lens of the film (more specifically, the peripheral dimming correction process to correct the decrease in the brightness of the periphery of the image due to the peripheral dimming of the lens, the lens distortion aberration These correction processes are hereinafter referred to as “LF aberration correction processes”, such as distortion aberration correction for correcting geometric distortion of an image caused, magnification chromatic aberration correction for correcting color fringing of an image caused by chromatic aberration of magnification of a lens, and the like. Do. The LF aberration correction processing will be described later.

The image processing performed by the image processing unit 140B includes, for example, image enlargement / reduction, gradation conversion, color conversion, hypertone processing for compressing the gradation of an ultra-low frequency luminance component of the image, and granularity. Image processing (standard image processing) for improving the image quality of an output image, such as hyper sharpness processing in which sharpness is enhanced while suppressing the sharpness, may be mentioned. Further, image processing for intentionally changing the image tone (for example, image processing for finishing the output image in monotone, image processing for finishing the output image in portrait tone, image processing for finishing the output image in sepia tone, etc.), and image processing Image processing (for example, image processing for finishing a person present in an original image on the main image to make it slender) or the like, each image (or a group of images recorded on one photographic film). The image processing unit 140B may be configured to be able to execute non-standard image processing to be selectively executed in units of (images).

The image processor 140 is connected to the input / output controller 134. The image data subjected to the image processing is temporarily stored in the frame memory 142 and then output to the input / output controller 134 at a predetermined timing. Note that the image processor unit 136B has the same configuration as the above-described image processor unit 136A, and a description thereof will be omitted.

In the present embodiment, each line image is read twice by the line CCD scanner 14 at different resolutions. In the first reading at a relatively low resolution (hereinafter, referred to as pre-scan), even when the density of the film image is extremely low (for example, a negative image of an underexposure in a negative film), a line CCD is used.
The reading of the entire surface of the photographic film is performed under the reading conditions determined so that the accumulated charge does not saturate (the amount of light irradiating the photographic film in each of the R, G, and B wavelength ranges, and the charge storage time of the line CCD). Done. Data (pre-scan data) obtained by this pre-scan is output from the selector 132 to the input / output controller 134.

An auto setup engine 144 is connected to the input / output controller 134. The auto setup engine 144 includes a CPU 146, a RAM 14
8 (for example, a DRAM), a ROM 150 (for example, a ROM whose storage content can be rewritten), and an input / output port 152.
These components are connected to each other via a bus 154. The pre-scan data output from the input / output controller 134 is stored in the pre-scan memory 13 shown in FIG.
After the data is temporarily stored in the storage unit 5, it is subjected to a setup calculation process in an auto setup engine 144 and a simulation image display process in a personal computer 158 (described later). Note that the prescan memory 135 is actually the RAM 148 of the auto setup engine 144 or the personal computer 1.
58 (described later) is used.

FIG. 4 shows the auto setup engine 14.
4 among various functions realized by the CPU 146.
The function of performing the setup calculation processing is shown as a setup calculation unit 144A. This setup operation unit 1
The 44A performs the setup calculation processing as follows. That is, the setup calculation unit 144A determines the frame position of the film image based on the pre-scan data input from the input / output controller 134, and converts data (pre-scan image data) corresponding to the film image recording area on the photographic film. Extract. Further, based on the pre-scanned image data, the size of the film image is determined, and image features such as density are calculated.
Determines the reading conditions when re-reading at a relatively high resolution (hereinafter, referred to as fine scan). Then, the frame position and the reading conditions are output to the line CCD scanner 14.

Further, the setup calculation section 144A performs image processing on image data (fine scan image data) obtained by performing fine scan by the line CCD scanner 14 based on prescan image data of film images for a plurality of frames. Are automatically determined by calculation, and the determined processing conditions are output to the image processor 140 of the image processor unit 136. The determination of the processing conditions of this image processing is performed by determining whether there are a plurality of film images capturing similar scenes based on the exposure amount at the time of capturing, the type of capturing light source, and other feature amounts, and determining a plurality of film images capturing similar scenes. Are determined, the processing conditions for image processing for these film images are the same or similar.

The optimum processing conditions for the image processing are as follows: whether the image data after the image processing is used for recording an image on photographic paper in the laser printer unit 18 or for displaying on a display means such as a display. It also changes depending on whether it is stored in the information recording medium or the like. Since the image processing unit 16 is provided with two image processor units 136A and 136B, for example, in a case where image data is used for recording an image on photographic paper and output to the outside, the setup calculation unit 144A Performs a set-up operation for each application, determines optimum processing conditions for each application, and outputs it to the image processor units 136A and 136B. Thus, the image processors 136A and 136B perform image processing on the same fine scan image data under different processing conditions.

Further, the setup calculation section 144A defines the gray balance and the like when the laser printer section 18 records an image on photographic paper based on the prescanned image data of the film image input from the input / output controller 134. The image recording parameters are calculated, and are simultaneously output when outputting the recording image data (described later) to the laser printer unit 18. Also, the auto setup engine 14
Reference numeral 4 also determines the image processing conditions for the file image data input from the outside by calculation in the same manner as described above.

The auto setup engine 144
In the ROM 150, LF aberration correction data used in the LF aberration correction processing described above is stored in advance for each type of lens used for various types of films with lenses. The LF aberration correction data according to the present embodiment is composed of three types of correction data: peripheral dimming correction data, distortion aberration correction data, and chromatic aberration of magnification correction data. LF
The aberration correction data corresponds to information related to the characteristics of the lens according to the present invention.
It has a function as an F aberration data storage unit 144B (storage means).

The peripheral dimming correction data is data used for peripheral dimming correction for correcting a decrease in brightness at the peripheral portion of an image due to peripheral dimming of a lens. The fluctuation of the light receiving amount (exposure amount) at each position on the image is set for each of the various lenses based on the result of measuring each of the various lenses. In the present embodiment, the coefficients a ₁ and a _{1 of} the correction exposure amount calculation expression (see the following expression (1)) used for the peripheral dimming correction are used as the peripheral dimming correction data.
Have adopted a _2, a _3.

Corrected exposure amount logE (r) = a ₁ r + a ₂ r ² + a ₃ r ³ (1) where r represents the distance from the center position of the image. The coordinate value (x, y) of an arbitrary pixel on the image and the center position (x _P0 , y _P0 ) of the image represented by the xy coordinate system (see FIG. 5A) with the corner of the image as the origin. The coordinate value (x _P , y _P ) of an arbitrary pixel on the image represented by the x _P y _P coordinate system (see FIG. 5B) with the origin (= (0, 0)) and the distance r Has the relationship shown in the following equation (2).

R = √ (x _P ² + y _P ² ) = √ ((xx _{P 0} ) ² + ( _{yy P 0} ) ² ) (2) Peripheral dim correction data (coefficient of correction exposure amount calculation formula) a ₁ , a
₂ , a ₃ ) are set for each type of lens so that the fluctuation of the exposure amount at each position on the film image when various types of lenses are used is corrected.

The distortion correction data is data used for distortion correction for correcting geometric distortion of an image caused by lens distortion, and is used at each position on a film image caused by lens distortion. The change direction and the change amount of the pixel position are set for each of the various lenses based on the measurement results of the various lenses. In the present embodiment, G is adopted as the reference color, and the measurement result of the amount of change in the pixel position (the amount of distortion) for G at each position on the film image due to the distortion of the lens is used as distortion correction data. decomposed in the x direction (direction perpendicular to the x direction) and the y-direction (longitudinal direction of the photographic film), the amount of distortion at each position on the image, based on the x _P y _P coordinate system, x
Direction distortion amount Dx (x _P, y _P) and y-direction distortion amount Dy (x _P, y _P) is using the data represented by.

The chromatic aberration of magnification correction data is data used for chromatic aberration of magnification correction for correcting color fringing of an image caused by chromatic aberration of magnification of a lens, and is used as a reference at each position on a film image caused by chromatic aberration of magnification of a lens. The change direction and the change amount of the pixel position of the non-reference color with respect to the pixel position of the color are set for each of the various lenses based on the measurement results of the various lenses.

In this embodiment, R and B are used as non-reference colors.
And the change amount of the R pixel position with respect to G at each position on the film image caused by the magnification chromatic aberration of the lens (magnification chromatic aberration amount)
Measurements were decomposed into the x direction and y direction, the magnification chromatic aberration amount of R at each position on the image, x _P y As _P coordinate system relative to the magnification chromatic aberration amount in the x direction R DerutaRx (x _P, y _P )
And lateral chromatic aberration amount ΔRy (x _P, y _P) in the y direction R are using the data represented by. Also, as the magnification chromatic aberration correction data of B, the measurement result of the amount of change in the pixel position of B with respect to G (the amount of chromatic aberration of magnification) at each position on the film image due to the chromatic aberration of magnification of the lens is decomposed in the x direction and the y direction. Then, the chromatic aberration of magnification at each position on the image is represented by x _P
y The chromatic aberration of magnification Δ in the x direction of B with reference to the _P coordinate system.
Bx (x _P , y _P ) and the lateral chromatic aberration ΔB of B in the y direction
y (x _P, y _P) is using the data represented by.

The input / output controller 134 is an I / F circuit 1
It is connected to the laser printer section 18 via 56.
When the image data after image processing is used for recording an image on photographic paper, the image data processed by the image processor 136 is transferred from the input / output controller 134 via the I / F circuit 156 to the recording image. The data is output to the laser printer unit 18 as data. The auto setup engine 144 is connected to a personal computer 158. When the image data after the image processing is output to the outside as an image file, the image data processed by the image processor unit 136 is sent from the input / output controller 134 to the auto setup engine 144.
Is output to the personal computer 158 via the.

The personal computer 158 has a CPU
160, memory 162, display 164, keyboard 166 (keyboard 166A and keyboard 1 in FIG. 2).
66B), Hard Disk 168, CD-ROM
Driver 170, transport control unit 172, expansion slot 17
4. An image compression / decompression unit 176 is provided, which is connected to each other via a bus 178. The display 164 corresponds to the display means described in claim 4, and the keyboard 166 corresponds to the input means described in claim 4.

FIG. 4 shows, among the various functions realized by the CPU 160 of the personal computer 158, a function related to the simulation image display processing by a plurality of blocks (that is, a prescan image data processing unit 158A, an image display unit 158B) for each function. And key correction input unit 1
58C). The pre-scan image data processing unit 158A takes in the pre-scan image data extracted from the pre-scan data by the setup operation unit 144A and re-stored in the pre-scan memory 135 from the pre-scan memory 135, and is determined by the setup operation unit 144A. Based on the acquired processing conditions, image processing equivalent to the image processing performed by the image processor 140 on the fine-scan image data is performed on the pre-scan image data based on the captured processing conditions, thereby obtaining simulation image data. Generate.

The image display section 158B has a display 164.
The simulation image data generated by the pre-scan image data processing unit 158A is converted into a signal for displaying an image on the display 164, and the simulation image is displayed on the display 164 based on the signal. I do. The key correction input section 158C includes a keyboard 166,
The operator performs verification of image quality or the like on the simulation image displayed on the display 164, and when information for instructing correction of processing conditions is input via the keyboard 166 as a verification result, the information is transmitted to the auto setup engine 144 ( Setup operation section 144A)
Output to Thereby, the setup operation unit 144A
In, processing such as recalculation of processing conditions of image processing is performed.

On the other hand, the transport control section 172 has a line CCD
It is connected to a film carrier 38 set on the scanner 14 and controls the transport of the photographic film by the film carrier 38. Also, the film carrier 38 has A
When the PS film is set, information (for example, print size) read by the film carrier 38 from the magnetic layer of the APS film is input.

A driver (not shown) for reading / writing data from / to an information storage medium such as a memory card, and a communication control device for communicating with other information processing devices are provided via the expansion slot 174. Connected to the personal computer 158. I / O controller 134
When image data for output to the outside is input from an external device (such as the driver or the communication control device) as an image file via the expansion slot 174,
Is output to When file image data is input from outside via the expansion slot 174, the input file image data is output to the input / output controller 134 via the auto setup engine 144. In this case, the input / output controller 134 outputs the input file image data to the selector 132.

(Operation) Next, as an operation of the present embodiment, a film image recorded on a photographic film is
A case will be described in which the image data is read by the D scanner 14 and various image processes are performed on the image data obtained by the reading and output.

As described above, the line CCD scanner 14 reads twice from the film image recorded on the photographic film (pre-scan and fine scan). The prescan is performed by the line CCD scanner 14 over the entire surface of the photographic film to be processed (read), and when the prescan data is input from the line CCD scanner 14 to the image processing unit 16, the input prescan data For the line scanner correction unit 1
22, dark correction, density conversion, shading correction,
Each process of defective pixel correction is performed.

The pre-scan data output from the line scanner correction unit 122 is temporarily stored in the pre-scan memory 135 via the selector 132 and then taken into the auto setup engine 144, and the (setup calculation unit 144A of the auto setup engine 144) )
The prescanning process is executed by the personal computer 158 (the prescanned image data processing unit 158A and the image display unit 158B). Hereinafter, this pre-scan processing will be described with reference to the flowchart of FIG. FIG. 6 shows the flow of the prescan processing for a single film image. However, in practice, the prescan processing described below is performed on a plurality of film images recorded on the same photographic film. Are performed in parallel.

In step 300, the screen position (frame position) of the film image recorded on the photographic film is determined based on the prescan data fetched from the prescan memory 135. The determination of the screen position is performed by determining the edge positions on both sides (upstream and downstream) along the photographic film transport direction (longitudinal direction of the photographic film) and both sides along the width direction of the photographic film orthogonal to the transport direction. (The position of the outer edge of the image).

The determination of the edge positions on both sides in the longitudinal direction of the film can be made by the applicant of the present invention, for example, in JP-A-8-304933, JP-A-8-304933 and JP-A-8-304.
As proposed in Japanese Unexamined Patent Publication No. 934/934 and Japanese Unexamined Patent Publication No. Hei 8-304935, a density change value along the film longitudinal direction is calculated for each pixel based on the density value for each pixel represented by the prescan data. This can be performed by integrating the density change value of each pixel along the film longitudinal direction in line units along the film width direction, and comparing the integrated value for each line. As for the determination of the edge position on both sides in the film width direction, similarly to the above, the density change value along the film width direction is calculated for each pixel, and the density change value along the film width direction of each pixel is calculated as the film length. This can be performed by integrating the data in units of lines along the direction and comparing the integrated value of each line. If the photographic film 22 is an APS film, an area where an edge may be present from a position where perforation is formed is set as a search range, and an edge is searched within the search range. It is also possible to shorten the time required for determining the edge position.

In the next step 302, step 300
Is transferred from the auto setup engine 144 to the personal computer 158, and the image display unit 158B of the personal computer 158 displays the screen position determination result on the display 164. As shown in FIG. 7 as an example, the display of the screen position determination result is performed by displaying an image representing the appearance of the photographic film based on the prescan data and by displaying a frame representing the screen position determination result (broken line in FIG. 7). Is superimposed on the image to display the screen position determination result to the operator, and the operator can easily determine whether the displayed determination result is appropriate or not. . Step 302 corresponds to the display control means described in claim 4.

In step 304, it is determined whether or not the result of the determination of the screen position displayed in step 302 is appropriate by the operator. If the determination in step 304 is negative, the process proceeds to step 306, where it is determined whether or not information instructing to correct the screen position determination result has been input. If this determination is also negative, step 304
And steps 304 and 306 are repeated. When determining that the determination result of the screen position is “proper”, the operator operates the keyboard 166 or the like and inputs information indicating that the determination result is “proper”. As a result, the determination at step 304 is affirmed, and the routine goes to step 312.

When the operator determines that the screen position determination result is "inappropriate" (as an example in FIG. 7,
An instruction is given to correct the determined screen position by performing an operation such as pressing an arrow key (not shown) of the keyboard 166, or the like, when the determined screen position is shifted from the actual screen position. I do. Thereby, step 306 is executed.
Is determined, the screen position determination result is corrected according to the input correction instruction (step 308), and the display on the display 164 is switched (step 310) according to the corrected screen position determination result, and step 304 is performed. Return to
Therefore, even when the screen position determined in step 300 is deviated from the actual screen position, the determination result of the screen position is corrected according to the instruction from the operator so as to match the actual screen position. Step 308 corresponds to “correction of the screen position determination result” by the calculating means.

In step 312, image data (pre-scan image data) corresponding to one frame of film image is cut out from the pre-scan data based on the screen position determined in the above processing. Step 314
Then, based on the pre-scan image data cut out from the pre-scan data, various image features such as the density of a specific film image corresponding to the cut pre-scan image data are calculated, and based on the calculated image features. , The reading conditions when the line CCD scanner 14 performs the fine scan of the specific film image are calculated.

In the next step 316, it is determined whether or not LF aberration correction is to be performed on the image data. In the present embodiment, the LF aberration correction processing is performed only when the image data to be processed is image data representing a film image captured and recorded on a photographic film by a film with a lens. Whether the image data to be processed is image data representing a film image photographed and recorded on the photographic film by the lens-equipped film is determined by storing the photographic film used as the lens-equipped film in the body of the lens-equipped film. Since it is brought into the image processing system in the state where it is done, for example, when taking out the photographic film from the body of the film with the lens, the type of the film with the lens is determined, A mark indicating whether an image has been shot is added to the photographic film, or, if the film has a magnetic layer, an identification code indicating the same information as the mark is recorded on the magnetic layer. Or by detecting whether or not the identification code is recorded. When the film with lens is manufactured, the mark may be provided on a photographic film used as the film with lens, or the identification code may be recorded on the magnetic layer.

If the determination in step 316 is negative, the process proceeds to step 318, where the size of the film image and the output image (the image to be recorded on photographic paper, the image to be displayed on the display, or the image to be stored in the information recording medium) The enlargement / reduction ratio in the enlargement / reduction processing for the fine scan image data is set in accordance with the size of the image represented by the data), and the process proceeds to step 338. Step 3
If the determination in step 16 is affirmative, the process proceeds to step 320, where LF correction processing is performed on the prescanned image data in steps 320 to 336.

That is, in step 320, based on the pre-scan image data cut out in step 312, the number of pixels x _{0 of the} pre-scan image data along the x direction (the longitudinal direction of the photographic film: see FIG. 5A). , Y
The pixel number y ₀ of the prescan image data along the direction (the width direction of the photographic film: see FIG. 5A) is calculated. In the next step 322, as the pixel at the center position of the image,
From the pixel corresponding to the corner of the film image (the origin shown in FIG. 5A), (x _0/2 ) th in the x direction and (y
_0/2 ) pixel (coordinates (x _P0 , y
Pixels _{P0): x P0 = x 0} /2, y P0 = y 0/2) to extract.

Note that the above steps 320 and 322
This corresponds to the calculation of the center position of the image by the calculating means of the present invention (more specifically, the calculating means according to claim 4). Further, since the above processing is performed using the prescanned image data, it also corresponds to the calculating means according to the third aspect.

In the next step 324, the type of lens used for photographing the film image represented by the pre-scan image data is determined. The type of the lens can be determined by reading the mark or the identification code described above and determining the type of the lens-equipped film that has captured and recorded the image on the photographic film. In step 326, the peripheral dimming correction data corresponding to the lens type determined in step 324 is fetched, and the peripheral dimming correction is performed according to the above equation (1) using the fetched peripheral dimming correction data.

In the vignetting correction, the following processing is performed on the data of each pixel. That is, first, the coordinate value (x, y) of the pixel to be processed in the xy coordinate system and the coordinate value (x _P0 , y _P0 ) of the pixel extracted as the center position of the image in step 322 are obtained in the above (2). )
The distance r of the pixel to be processed from the image center is calculated. Next, the distance r is substituted into the equation (1) together with the previously acquired peripheral dimming correction data (coefficients a ₁ , a ₂ , a ₃ ) to obtain a corrected exposure log E. And the exposure of the photographic film-
The corrected exposure amount logE is converted into a corrected density value based on the density characteristics, and the density value of the pixel to be processed is shifted by the corrected density value. As a result, a decrease in the brightness of the peripheral portion of the image due to the peripheral dimming of the lens is corrected.

The operation of the equation (2) is performed in step 322.
This is equivalent to normalizing the coordinate value (x, y) of each pixel with reference to the center position of the image calculated in the above. The peripheral dimming correction is performed based on the center position of the image. It is possible to correct with high accuracy a decrease in the brightness of the peripheral portion of the image due to light.

In the next steps 330 to 334, distortion correction and lateral chromatic aberration correction are performed on the prescanned image data. That is, in step 330, step 32
The distortion correction data and the chromatic aberration of magnification correction data corresponding to the lens type determined in step 4 are fetched, and the original data of each pixel of the prescan image data is corrected based on the fetched distortion aberration correction data and the chromatic aberration of magnification correction data. The pixel position (the pixel position when there is no lens distortion and chromatic aberration of magnification) is calculated for each of R, G, and B.

In this calculation, the coordinate value (x, x) of each pixel is determined with reference to the center position of the image calculated in step 322.
y) The x _P y _P coordinate system coordinate values in (see FIG. 5 (B) refer) (x _P, converted to _{y P) (x P = x} -x P0, y P = y-y
_P0: That normalized), and the coordinate value after normalization is (x _P,
With respect to the pixel of y _P , the coordinates (x _P , y _P ) are used as keys, and the corresponding distortion amounts Dx (x _P , y _P ) and Dy (x _P ,
y _P ), lateral chromatic aberration ΔRx (x _P , y _P ), ΔRy
(X _P , y _P ), ΔBx (x _P , y _P ), and ΔBy
(X _P , y _P ) is searched, and data R (x _P , y _P ) representing density values of R, G, and B colors of a pixel at coordinates (x _P , y _P )
y _P ), G (x _P , y _P ), and B (x _P , y _P ) are converted by the following equations (3) to (5).

R (x _PR , y _PR ) ← R (x _P , y _P ) (3) where x _PR = x _P + ΔRx (x _P , y _P ) + Dx (x _P , y _P ) y _PR = _{y P + ΔRy (x P,} y P) + Dy (x P, y P) G (x PG, y PG) ← G (x P, y P) ... (4) _{However, x PG = x P + Dx} (x P , Y _P ) y _PG = y _P + Dy (x _P , y _P ) B (x _PB , y _PB ) ← B (x _P , y _P ) (5) where x _PB = x _P + ΔBx (x _P , y _P ) + Dx (x _P , y _P ) y _PB = y _P + ΔBy (x _P , y _P ) + Dy (x _P , y _P )

By the way, a film image photographed and recorded on a photographic film by a film with a lens has a geometrical distortion (so-called pincushion type distortion) as shown in FIG. FIG. 8 shows an example in which an image in which a large number of lines are arranged in a grid pattern is photographed and recorded on a photographic film using a film with a lens. If distortion correction is performed on an image in which the above-described geometric distortion occurs, the outer edge of the image has a so-called barrel shape as shown in FIG. (Blank areas shown near the four corners of the image in FIG. 8B: hereinafter referred to as image missing areas) occur. Therefore, when the distortion is corrected, the image data used as the output image (for example, FIG. 8) is used based on the image data after the correction of the distortion so that the image lacking area is not included in the output image.
It is necessary to cut out the image data in the range indicated by the dashed line in (B) and to perform the scaling process on the cut out image data according to the size of the output image.

The size of the image missing area (image missing amount) changes depending on the magnitude of lens distortion. For this reason, in the next step 332, the distortion amount Dx,
An image missing amount is calculated based on Dy. In the next step 334, the enlargement / reduction ratio is set based on the image missing amount calculated in step 332 and the size of the simulation image for testing such as the processing conditions of the image processing to be displayed on the display 164, and the set enlargement / reduction is set. Interpolation according to rate
Perform scaling processing.

In step 330, the coordinates of each pixel of the image data are transformed according to the distortion and chromatic aberration of magnification of the lens. In most cases, it is shifted. For this reason, in the interpolation / enlargement / reduction processing, the image data that has undergone the coordinate conversion in step 330 is subjected to the enlargement / reduction processing according to the size of the simulation image in accordance with the previously set enlargement / reduction ratio, and then is moved to the grid point position. The density value of each of the R, G, and B pixels is represented by the density of each of the R, G, and B pixels located around the lattice point on the image represented by the image data after the scaling processing. It is obtained from the value by interpolation.

In the above description, since the coordinate value (x, y) of each pixel is standardized on the basis of the center position of the image, distortion and chromatic aberration of magnification are corrected on the basis of the center position of the image. The geometric distortion and the color blur due to the correction of the distortion and the chromatic aberration of magnification are corrected with high accuracy, and the image data subjected to the enlargement / reduction processing for removing the image missing area can be obtained.

The enlargement / reduction ratio for the fine scan image data also changes depending on the size of the output image. Therefore, in the next step 336, the original enlargement / reduction ratio determined from the size of the film image and the size of the output image is corrected in accordance with the image missing amount calculated in step 332, thereby interpolating / enlarging the fine scan image data. Set the enlargement / reduction ratio in the reduction process.

In the next step 338, various image feature amounts of the film image are calculated based on the pre-scan image data, and the image processing conditions for the fine scan image data are calculated based on the calculated image feature amounts. After the determination, the prescan image data is transferred to the personal computer 158 via the prescan memory 135, and the processing conditions for image processing on the fine scan image data are transferred to the personal computer 158.

Thus, the personal computer 15
In step 8, the image verification processing is performed in the next step 340.
That is, the prescanned image data processing unit 158A presses image processing equivalent to the image processing executed by the image processor 140 on the fine scan image data based on the processing conditions of the image processing transferred from the auto setup engine 144. This is performed on the can image data to generate simulation image data. Further, the image display unit 158 uses the fine scan image data after the image processor 140 executes the image processing based on the simulation image data generated by the pre-scan image data processing unit 158A to create a print. The displayed simulation image is displayed on the display 164.

When the simulation image is displayed on the display 164, the operator visually checks the simulation image and determines whether or not the image quality of the simulation image is appropriate (that is, the processing conditions of the standard image processing calculated by the auto setup engine 144). The information indicating the result of the test is input via the keyboard 166. In the next step 344, it is determined whether or not information instructing the correction of the processing condition has been input from the operator as information representing the test result.

If the operator inputs information instructing the correction of the processing conditions of the image processing, step 34 is executed.
If the determination in step 4 is affirmative, the process proceeds to step 346, in which the auto setup engine 144 corrects the processing conditions according to the input correction instruction, and then proceeds to step 33.
Return to 8. As a result, the simulation image 300 corrected according to the input correction instruction is displayed again on the display 164. When the operator visually confirms the redisplayed specific simulation image, the operator can easily determine whether or not the content of the previously input correction information is appropriate. Then, when the operator inputs the information indicating the pass of the test, the determination in step 344 is denied, and the image test process, that is, the pre-scan process ends.

On the other hand, when the pre-scan for the photographic film is completed, the line CCD scanner 14 performs a fine scan for reading the photographic film for each film image. At the time of this fine scan, reading conditions for each film image are notified to the line CCD scanner 14 from the auto setup engine 144, and the line CCD scanner 14 reads each film image (fine scan) according to the notified reading conditions. Do.

The processing conditions of image processing for each film image are notified from the auto setup engine 144 to the image processor 140 when fine scan image data of each film image is input from the line CCD scanner 14. Image processor 14
0 performs image processing of the notified processing contents on the input fine scan image data of each film image.

Here, if the photographic film set in the line CCD scanner 14 is a photographic film in which an image is captured and recorded by a film with a lens, the LF aberration correction unit 140 of the image processor 140
A performs the same processing as in steps 320 to 334 of the pre-scan processing described above on the fine scan image data (however, the interpolation / enlargement / reduction processing described in step 334 sets the enlargement / reduction ratio to step 33).
Use the enlargement / reduction ratio calculated in 6). Thereby, on the basis of the center position of the image, a decrease in the brightness of the peripheral portion of the image due to dimming around the lens, geometric distortion and color blur due to lens distortion and magnification chromatic aberration correction are corrected with high accuracy, and Image data that has undergone enlargement / reduction processing so as to remove the image missing area and match the size of the output image is obtained.

The fine scan image data input to the image processor 140 is subjected to various types of image processing by the image processing unit 140B in addition to the above-described image processing, and then output as image data to the image processor 140.
Output from This output image data is used for recording an image on photographic paper in the laser printer unit 18, for displaying an image on the display 164, or for storing information in a memory card or the like via the expansion slot 174. Stored on the medium.

In the above description, LF aberration correction (correction of image quality deterioration due to lens characteristics) includes correction of a decrease in the brightness of the peripheral portion of an image due to dimming around the lens, and correction due to distortion of the lens. Correction of the geometric distortion of the image to be performed and correction of the color fringing of the image caused by the chromatic aberration of magnification of the lens have been described. However, the present invention is not limited to this. For example, at least one of the above corrections is performed. The correction may be performed, or another correction such as a correction of a decrease in sharpness of an image due to a curvature of field of a lens or the like may be performed.

In the above description, the image data to be processed is
Only when the image data represents a film image captured and recorded on a photographic film by a film with a lens,
The correction of the image quality deterioration caused by the characteristics of the lens has been performed. However, the present invention is not limited to this, and the image data to be processed may have the characteristics of the lens such as a relatively inexpensive compact camera. Image data representing a film image captured and recorded on a photographic film by a camera having a high degree of image quality deterioration due to image quality, or to an information recording medium by imaging with a digital camera having a large degree of image quality deterioration due to lens characteristics. The above-described correction may be performed even when the image data is stored. Also, regardless of the degree of image quality deterioration due to the characteristics of the lens, all image data representing an image recorded on a recording material using a lens, and all image data obtained by imaging using a lens The above-described correction may be performed for

When image data obtained by reading an image recorded on a recording material such as a photographic film by an image reading device such as a line CCD scanner 14 is used as the image data to be processed, the image data The deterioration of the image quality due to the characteristics of the lens provided in the reading device may be corrected together.

[0090]

As described above, according to the first aspect of the present invention, the screen position of an image is determined based on data obtained by reading a recording material on which an image is projected and recorded via a lens. The center position of the image is calculated, and based on the information related to the characteristics of the lens, the image data represented by the image data is compared with the image data based on the center position of the calculated image. Since the deterioration is corrected, the image data obtained by reading the image recorded on the recording material can be highly accurately corrected for the deterioration of the image quality caused by the characteristics of the lens. Has an effect.

According to a third aspect of the present invention, in the first aspect of the present invention, the center position of an image is calculated based on preliminary read data obtained by preliminary reading a recording material at a predetermined resolution. In addition to the above-described effects, in addition to the above-described effects, image quality deterioration due to lens characteristics is corrected for main read data obtained by performing main read in which a material is read at a resolution higher than a predetermined resolution. Can be calculated in a short time.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the screen position determination result is displayed on the display means, and information for instructing correction of the screen position determination result is input via the input means. In such a case, the determination result of the screen position is corrected in accordance with the instruction, and the calculation of the center position is performed based on the corrected screen position. This also has the effect of preventing the accuracy of correction of image quality deterioration due to the characteristics of the lens from being reduced.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a digital laboratory system according to an embodiment.

FIG. 2 is an external view of a digital laboratory system.

FIG. 3 is a block diagram illustrating a schematic configuration of an image processing unit.

FIG. 4 is a block diagram illustrating functions of an auto setup engine and a personal computer of an image processing unit according to the first embodiment, divided into blocks, and showing an internal configuration of an image processor.

[5] (A) is the xy coordinate system set with respect to the film image, (B) is a conceptual diagram showing each of the x _P y _P coordinate system.

FIG. 6 is a flowchart showing the contents of a pre-scan process according to the embodiment.

FIG. 7 is an image diagram showing a display example of a screen position determination result.

FIGS. 8A and 8B are image diagrams each showing a geometric distortion of an image caused by lens distortion, and FIG. 8B showing an outer edge shape of an image represented by image data after distortion correction.

[Explanation of symbols]

 10 Digital Lab System 16 Image Processing Unit 140 Image Processor 140A LF Aberration Correction Unit 144 Auto Setup Engine 144A Setup Operation Unit 144B LF Aberration Data Storage Unit 158 Personal Computer 164 Display 166 Keyboard

Claims (4)

[Claims] Determining a screen position of the image on the recording material based on data obtained by reading a recording material on which the image is projected and recorded via a lens;
Calculating means for calculating the center position of the image based on the determined screen position; obtaining means for obtaining information relating to the characteristics of the lens; and information based on the information relating to the characteristics of the lens obtained by the obtaining means. Correction means for correcting the image data of the image, with reference to the center position of the image calculated by the calculation means, as to the image represented by the image data, the deterioration of the image quality caused by the characteristics of the lens; An image processing apparatus including: 2. The computing unit according to claim 1, wherein a position along a first direction substantially parallel to two of four sides forming an outer edge of the screen is based on the determined screen position. The center of both ends along the first direction, and the position along the second direction orthogonal to the first direction is the center of both ends along the second direction of the screen. The image processing apparatus according to claim 1, wherein the calculation is performed as a center position of the image. 3. The computer according to claim 1, wherein the calculating unit calculates a center position of the image based on preliminary reading data obtained by preliminary reading the recording material at a predetermined resolution. 2. The image processing apparatus according to claim 1, wherein the correction is performed on the main read data obtained by performing the main read for reading the material at a resolution higher than the predetermined resolution. A display means for displaying an image; a display control means for displaying a result of the screen position determination by the arithmetic means on the display means; and a correction of the screen position determination result displayed on the display means. Input means for inputting information for instructing, and wherein the arithmetic means responds to the instruction when information for instructing correction of a screen position determination result is input via the input means. The image processing apparatus according to claim 1, wherein the determination result of the screen position is corrected by using the calculated screen position, and the center position is calculated based on the corrected screen position.