JP2014220546A - Image recorder and image recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amount of additional data added to range reduction image data and to reduce adverse effects that an image becomes unnatural since the range reduction image data is gradation-adjusted.SOLUTION: An image recorder includes: an image signal generation section for generating image data of high gradation; a region detection section for detecting a region becoming a target of post processing from the generated high gradation image data; a calculation section for calculating a post processing evaluation value of the detected region; a range reduction section for compressing gradation of the high gradation image data and generating range reduction image data; an additional data generation section for generating additional data corresponding to data dissipated by the gradation compression by the range reduction section; and a recording section for associatively recording the reduction image data generated by the range reduction section and the additional data generated by the additional data generation section. The additional data generation section controls a generation method of the additional data in accordance with the post processing evaluation value calculated by the calculation section.

Description

  The present invention relates to an image recording apparatus such as a digital camera that records high gradation image data and a method thereof.

  Image recording devices such as digital cameras and digital video cameras photoelectrically convert captured subject images pixel by pixel using an image sensor such as a CMOS sensor or CCD, and convert them into video signals according to the light intensity for image signal processing. I do. In a scene where the dynamic range of the image sensor is narrow and the brightness difference between a bright subject and a dark subject is large, it is difficult to capture both subjects with appropriate exposure. In order to solve such a problem, a method has recently been proposed in which a plurality of images with different exposure amounts are photographed in the same scene, and a plurality of image data are combined to obtain an image with an expanded dynamic range. It has become. If the extended high dynamic range image data is recorded as it is, an enormous recording capacity is required, and the range width supported by the display device is also limited, so in reality it is impossible to record the high dynamic range image data as they are. . Therefore, it is necessary to reduce the range to 8 bits of image data, which is a standard range width, for recording.

  Patent Document 1 discloses an apparatus that records high dynamic range image data in a standard file format and can effectively use high dynamic range data at the beginning of imaging as necessary.

JP 2002-152680 A

  The configuration described in Patent Document 1 records the difference file deleted at the range reduction processing stage and the parameter that becomes the history of the difference file, and restores it using the editing software after shooting. is there. In Patent Document 1, it is possible to reproduce range-enlarged image data having a high dynamic range by using a difference file and parameters. However, in order to completely reproduce the range-enlarged image data, in addition to the load of calculating the difference data through the inverse conversion process, image data that is unlikely to be post-processed using editing software after shooting is also redundant. There was a problem of recording additional data.

  Accordingly, an object of the present invention is to reduce the amount of additional data to be added to the range reduced image data and to adversely affect an unnatural image by performing gradation adjustment on the range reduced image data. An object of the present invention is to provide an image recording apparatus and a method thereof that can be reduced.

  In order to achieve the above object, an image recording apparatus of the present invention is an image signal generating unit that generates high gradation image data, and is subjected to post-processing from the high gradation image data generated by the image signal generating unit. Area detection means for detecting an area, calculation means for calculating a post-processing evaluation value of the area detected by the area detection means, and range reduction for generating range-reduced image data by gradation-compressing the high-gradation image data Means, additional data generating means for generating additional data based on data lost by tone compression by the range reducing means, range reduced image data generated by the range reducing means, and generated by the additional data generating means And recording means for recording the additional data in association with each other, and the additional data generating means is a post-process calculated by the calculating means And controlling the method for generating additional data in accordance with the value.

  According to the present invention, the amount of additional data to be added to the range-reduced image data is reduced, and when the gradation adjustment is performed after shooting, a pseudo contour is generated in a flat region where a tone jump occurs and a change in luminance is small. It is possible to prevent an adverse effect such that an unnatural image occurs.

It is a block diagram showing the structure of the image recording device which concerns on Embodiment 1 of this invention. It is a detailed block diagram of an image processing unit according to the first embodiment of the present invention. It is a figure explaining the relationship between the pixel value before gradation correction of a gradation correction process, and after gradation correction. It is a detailed block diagram of the image analysis part which concerns on Embodiment 1 of this invention. It is a figure explaining the determination operation | movement of whether it is a flat area | region. It is an example of a post-processing evaluation value table. It is an operation | movement flowchart of the recording process which concerns on Embodiment 1 of this invention. It is an example of an additional data generation table. It is a conceptual diagram of a recording file format. It is a block diagram showing the modification of the image analysis part which concerns on Embodiment 1 of this invention. It is an operation | movement flowchart of the recording process which concerns on Embodiment 2 of this invention. It is an example of GUI of post-processing editing software.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of an image recording apparatus according to Embodiment 1 of the present invention. Hereinafter, an example applied to a digital camera as an example of an image recording apparatus will be described.

  In FIG. 1, an optical system 101 is a lens group including an imaging lens, a focus lens, and the like, and a drive system that controls zoom and focus. The lens group of the optical system 101 collects reflected light from the subject and forms a subject image on the image sensor 102. The image sensor 102 is an image sensor such as a CMOS sensor or a CCD, for example, and subjects the subject image formed by the optical system 101 to photoelectric conversion in units of pixels in accordance with the light intensity, and converts the analog image signal to the analog signal processing unit 103. Output to. The analog signal processing unit 103 performs signal processing such as noise removal and gain control on the input analog image signal and outputs the signal to the A / D conversion unit 104. The A / D conversion unit 104 A / D converts the analog image signal to which the signal processing is applied by the analog signal processing unit 103, and outputs the obtained digital image to the image processing unit 105. The image processing unit 105 performs various image processing on the digital signal output from the A / D conversion unit 104 according to the setting value stored in the ROM 113.

  For example, an example of a block diagram of the image processing unit 105 is shown in FIG. In FIG. 2, the digital signal output from the A / D conversion unit 104 is input to the image signal generation unit 201. The image signal generation unit 201 generates an R (red) signal, a G (green) signal, and a B (blue) signal from the input digital signal. For example, when a digital signal of a single-plate type Bayer arrangement in which the resolution of green is N / 2 and the resolution of red and blue is N / 4 with respect to the total number N of CCD pixels is input for each pixel. N R (red) signals, G (green) signals, and B (blue) signals are generated by interpolation using peripheral pixel values.

  The RGB signals generated by the image signal generation unit 201 are sent to the WB detection unit 202 and the WB processing unit 203, respectively. The WB detection unit 202 calculates a gain value of white balance suitable for the captured image from the captured image data. The WB processing unit 203 multiplies the RGB pixel values of the image by the white balance gain value obtained by the WB detection unit 202. The image data multiplied by the white balance gain value is temporarily recorded in the RAM 114. The image data and the feature amount of the image data obtained by image analysis by the image analysis unit 115 (not shown) are recorded in the RAM 114 every time the image is taken a plurality of times. The image analysis unit 115 will be described in detail later using a block diagram. The image data synthesis unit 204 generates a high dynamic range image by adding and synthesizing a predetermined number of image data with different exposures recorded in the RAM 114, and records the synthesized image in the RAM 114. The correction amount calculation unit 205 calculates the gradation correction amount based on the feature amount data of each image and the feature amount data of the composite image recorded in the RAM 114. For example, a correction amount is calculated such as gamma processing, black stretch processing for improving contrast by increasing gain in a dark portion, and knee processing for reducing bright portion to prevent overexposure.

The gradation compression unit 206 performs gradation correction on the composite image data recorded in the RAM 114 using the gradation correction amount output from the correction amount calculation unit 205, and outputs corrected composite image data. The gradation correction performed here includes linear processing and non-linear processing. FIG. 3 shows the relationship between pixel values before and after gradation correction in the gradation correction processing. The horizontal axis indicates the pixel value before gradation processing, the vertical axis indicates the pixel value after gradation processing, (a) indicates the linear processing, and (b) indicates the level conversion relationship of the nonlinear processing. The linear process shown in FIG. 3A is a process for linearly converting the level. For example, when reducing the range of a 14-bit video signal to an 8-bit video signal, it is possible to express 16384 levels and 8 bits can represent 256 levels, so that 16384/256 = 64, that is, 1/64 level compression. Will do. A lot of information is lost by this level compression. Specifically, using binary numbers, 14-bit data [11111010000100] ₂ = 16044 is divided by 64 and rounded to 8-bit data, resulting in a 6-bit shift to the left, resulting in [11111010] ₂ = 250. Even if this is multiplied by 64 and inverted, that is, shifted to the right by 6 bits, [11111010000000] ₂ = 16000, and the original data is not completely restored. On the other hand, the level conversion of the non-linear processing shown in (b) performs level compression using characteristics for realizing a natural image close to the impression seen by human eyes. Similar to the linear processing described above, the non-linear processing is not completely restored to the original data, the compression rate varies depending on the luminance, and the pixel value is low compressed in the low luminance portion and high compressed in the high luminance portion. become. Non-linear processing includes black stretch processing that improves contrast by increasing gain in dark portions, and knee processing that gains gain reduction in bright portions and prevents whiteout.

  In the present embodiment, an example in which the correction amount calculation unit 205 calculates the tone correction amount based on the feature amount data of each image and the feature amount data of the composite image analyzed by the image analysis unit 115 recorded in the RAM 114. As described above, the feature amount of each image may be used. That is, the gradation correction amount may be obtained from the table data previously set in the ROM 113 and the gradation correction processing may be performed by the gradation compression unit 206.

  In this embodiment, an example in which gradation correction is performed on the most commonly used 8-bit data has been described. However, the present invention is not limited to this as long as it follows a standard file format.

  Further, in the present embodiment, an example in which high dynamic range image data is generated by photographing and combining a plurality of predetermined image signals with different exposures has been described. However, an image with a high dynamic range can be generated. For example, it is not limited to this. For example, the sensor of the image sensor 102 may be a sensor that supports high bits. For example, the characteristics of various video signals such as a flat part, detail part, noise part, etc. are analyzed with respect to the input 8-bit pixel value, and the interpolation value is calculated to obtain 8 + n-bit, for example, 14-bit precision data. It may be configured to generate high gradation image data.

  The additional data generation unit 106 generates data to be added to the image data whose range has been reduced by the image processing unit 105. The codec unit 107 performs an encoding process on the digital image to which the image processing is applied by the image processing unit 105 in accordance with a data format recorded on a recording medium 108 described later, and outputs the encoded image to the recording medium 108. The codec unit 107 decodes the encoded image data recorded on the recording medium 108 and outputs the decoded image data to the image display unit 109 or the like. The recording medium 108 is an external recording medium that is detachably connected to the digital camera 100 such as a built-in memory of the digital camera 100, a memory card, or an HDD, and records an image captured by the digital camera 100. The image display unit 109 is a display device such as a small liquid crystal display (LCD), for example, and functions as an electronic viewfinder of the digital camera 100 by displaying through the digital image output from the image processing unit 105. Further, the image display unit 109 can display the image data decoded by the codec unit 107 as described above.

  The control unit 111 is a CPU, for example, and controls the overall operation of each block included in the digital camera 100. The operation input unit 112 is an input interface that is included in the digital camera 100 and detects user input such as a release button, menu button, touch panel, and the like, and transmits information input by a user operation to the control unit 111. The ROM 113 is a non-volatile read-only semiconductor memory, and in addition to an operation program for each block included in the digital camera 100, settings related to imaging of the digital camera 100, such as output resolution and recording image quality, and operation for each block are necessary. Stores setting values and the like. The RAM 114 is a volatile readable / writable memory, and is a RAM that develops operation constants, variables, programs read from the ROM 113, and the like. For example, the control unit 111 reads the operation program of each block included in the digital camera 100 stored in the ROM 113, develops the program in the RAM 114, and executes the program, thereby controlling the operation of each block included in the digital camera 100. The image analysis unit 115 analyzes the image data stored in the RAM 114 according to an instruction from the control unit 111.

FIG. 4 shows an example of a block diagram of the image analysis unit 115. The flat area detection unit 401 detects a flat area as a subject area from high gradation image data which is composite image data recorded in the RAM 114. For example, the R region, G component, and B component data of the pixel signal is input from the RAM 114 to the flat region detection unit 401, and threshold _values R _th and G _th that are threshold values of the R component, the G component, and the B component from the ROM 113, respectively. , _Bth set value is input. The flat region detection unit 401 detects whether or not the region is a flat region by detecting the presence or absence of changes in the R component, G component, and B component of the continuous pixel values.

  Next, as shown in FIG. 5, the input image data is divided into vertical and horizontal L × M, and a determination flag as to whether or not each block is a flat region is attached. The flat region area calculation unit 402 calculates the area of the flat region and the ratio of the flat region in the entire screen based on the flat region determination flag for each block detected by the flat region detection unit 401. In the present embodiment, whether or not a flat region is detected is detected by the continuity of pixel values. This is because, when there is a gradation-like change in which the pixel value changes slowly, it focuses on the fact that pseudo contours are generated and become conspicuous if the lower bits are lost by gradation compression. A detection method is proposed. However, since it is possible to determine whether or not the region is a flat region by detecting not only the continuity of pixel values but also the variance of pixel values as evaluation values, other embodiments of the present invention can be obtained. It becomes.

  The face detection unit / face recognition unit 404 detects a human face image and recognizes a face as main subject detection. In other words, the face portion that is the main subject is detected from the photographed image, and the face that matches the face registered in advance is recognized from the face of the person detected by the face detection unit. Known techniques can be applied to the face detection process and the face recognition process. For example, regarding the face detection process, an edge component of an image is detected by applying a bandpass filter to the image data under the control of the control unit 111. Thereafter, pattern matching is performed on the detected edge component, and a candidate group of eyes, nose, mouth, and ears is extracted. Then, the control unit 111 determines that an eye pair that satisfies a preset condition (for example, distance between two eyes, inclination, etc.) from the extracted eye candidate group is an eye pair. Narrow down only a certain candidate group. Then, the face candidate is detected by associating the narrowed-down eye candidate group with other parts (nose, mouth, ears) that form a face corresponding thereto, and through a preset non-face condition filter. As an example of face recognition processing, a person's face to be recognized as a main subject is photographed in advance and recorded (registered) in the RAM 114 before photographing. Then, by comparing the feature amount of the face detected by the above-described face detection processing with the feature amount of the face of the recorded (registered) person, which detected face is which person's face is specified.

  The post-processing evaluation value calculation unit 403 calculates a post-processing evaluation value for the post-processing target region according to the calculation result of the flat region area calculation unit 402 and the detection result of the face detection unit / face recognition unit 404.

  FIG. 6 shows an example of a post-process evaluation value table used for calculating the post-process evaluation value. In the post-processing evaluation value table, the area ratio of the entire flat area screen calculated by the flat area calculation unit 402 is S, the face detection evaluation value by the face detection / face recognition unit 404 is P, and the face recognition evaluation value is Q. Represent. And it is the table which matched the post-processing evaluation value corresponding to each evaluation value as the post-processing evaluation value A and the post-processing evaluation value B. Reference numeral 601 denotes an area ratio S of a flat region, 602 denotes a post-processing evaluation value A, 603 denotes a face detection evaluation value P / face recognition evaluation value Q, and 604 denotes a post-processing evaluation value B. For example, if the area ratio of the flat region is large in the image data and the face data is recognized as pre-recorded in the RAM 114, the post-processing evaluation values A and B are high. Conversely, when the area ratio of the flat region is small and no face is detected, the post-processing evaluation values A and B are low.

  The configuration of the digital camera 100 and the operation of each block in the present embodiment have been described above. As described above, the digital camera 100 can encode an image captured through the optical system 101 and add it to a recording medium.

  Next, the recording process of the digital camera 100 will be described in detail using the flowchart of FIG. FIG. 7 is an operation flowchart of a recording process according to the first embodiment of the present invention. The flowchart of FIG. 7 illustrates a processing procedure executed by controlling each processing block by the control unit 111. The control unit 111 expands a program stored in the memory (ROM) into the memory (RAM). However, this is realized by the execution of the CPU.

  In step S701, the image processing unit 105 generates high gradation image data. In the present embodiment, the image data combining unit 204 included in the image processing unit 105 generates high gradation image data by combining a plurality of images with different exposures. In step S <b> 702, the image analysis unit 115 detects a flat area of the high gradation image data output from the image data synthesis unit 204 included in the image processing unit 105 using the flat area detection unit 401. In step S703, the image analysis unit 115 calculates the area of the flat region detected in step S702 and the area ratio in the entire screen.

  In step S <b> 704, the control unit 111 determines whether the area ratio of the flat region calculated in step S <b> 703 is larger than an arbitrary threshold setting value recorded in advance in the ROM 113. If it is determined that the flat region is larger than the arbitrary threshold setting value, the process proceeds to step S705. If it is determined that the flat area is smaller than an arbitrary threshold value, the process proceeds to step S709.

  In step S705, the post-processing evaluation value calculation unit 403 included in the image analysis unit 115 calculates the area ratio calculated by the flat region area calculation unit 402, the face detection evaluation value calculated by the face detection unit / face recognition unit 404, and face recognition. A post-processing evaluation value is calculated according to the evaluation value. For example, when the post-process evaluation value A is 30 and the post-process evaluation value B is 40 using the post-process evaluation value table shown in FIG. The processing evaluation value is calculated as 30 + 40 = 70.

  In step S706, the gradation compression unit 206 included in the image processing unit 105 generates range reduced image data based on the correction amount of the correction amount calculation unit 205. In step S707, the additional data generation unit 106 generates additional data according to the post-processing evaluation value calculated by the post-processing evaluation value calculation unit 403 in step S705. For example, the additional data generation unit 106 generates additional data based on the additional data generation table shown in FIG. The additional data generation table will be described later.

  In step S708, the image data generated by the image processing unit 105 and the additional data generated by the additional data generating unit 106 are associated with each other and recorded on the recording medium 108. How to associate and record will be described later with reference to FIG. In step S709, when the ratio of the entire flat area in step S704 is smaller than a predetermined threshold value (set value), only the reduced range image data is recorded without recording the additional data.

  The additional data generation table shown in FIG. 8 is a table showing the correspondence between the post-processing evaluation value calculated by the post-processing evaluation value calculation unit 403 and the lower bit width of the additional data generated by the additional data generation unit 106. Reference numeral 801 denotes a post-processing evaluation value calculated by the post-processing evaluation value calculation unit 403, and 802 denotes a lower bit width of the additional data. For example, when 14-bit high gradation image data generated by the image data composition unit 204 is subjected to range reduction to 8-bit range reduced image data by gradation processing, the lost lower 6 bits are set to 1 according to the post-processing evaluation value. 6 bits to 6 bits are the target of additional data. The additional data generation unit 106 compresses the target lower bits by the codec unit 107. For example, according to the post-process evaluation value table shown in FIG. 6, the post-process evaluation value calculation unit 403 allows the final post-process evaluation value when the post-process evaluation value A is 30 and the post-process evaluation value B is 40. The value is obtained by adding 30 + 40 = 70. Next, when the post-processing evaluation value is 70, the additional data generation unit 106 determines that the lower bit width of the additional data is 4 bits according to the additional data generation table of FIG.

  FIG. 9 shows a conceptual diagram of the recording file format of the recording medium 108. According to the present embodiment, the reduced range image data output from the image processing unit 105 and the additional data output from the additional data generation unit 106 are encoded by the codec unit 107 and recorded on the recording medium 108. The range-reduced image data is image data in a standard format, for example, 8-bit JPEG compression format data. On the other hand, the additional data is data that has a higher compression efficiency than the upper bits and is highly compressed in the codec unit 107 for the bit width of the lower bits that are lost based on the additional data generation table of FIG. In this embodiment, the encoding compression rate of the additional data is increased because the main image does not fail even if there is no main data like the main image. The encoding compression rate is higher than that of image data.

  In addition, since the generation pattern of the lower bits of the additional data has a low correlation for each pixel and occurs in a form that depends on the occurrence probability, using arithmetic coding or the like that efficiently encodes and compresses the occurrence probability, Furthermore, it is possible to perform encoding and compression with high efficiency.

  As a method of associating the additional data with the image data, the case where all the additional data is embedded in the range-reduced image data as shown in FIG. It may be added to image data. In the example of FIG. 9A, the generated additional data is embedded after the image data. However, the embedded position is not limited to this, and may be embedded in the header portion of the image data. In FIG. 9A, reference numeral 901 denotes image data, for example, JPEG compression data. Reference numerals 902, 903, and 904 denote additional data blocks, reference numeral 902 denotes a block header of additional data, reference numeral 903 denotes a body of additional data, and reference numeral 904 denotes a footer of additional data. The header 902 and the footer 904 record identification information, size, and the like of the additional data block in order to correctly recognize whether the additional data is connected to the image data. In FIG. 9B, reference numeral 905 denotes image data, reference numeral 906 denotes additional data information, and reference numeral 907 denotes additional data. By adding only the additional data information 906 to the image data 905, the additional data 907 is associated with the image data. In the example of FIG. 9B, only the file name is added as the information of the additional data generated after the image data, and the additional data exists separately. The position to be added is not limited to this, and the information of the additional data may be added to a part of the header of the image data. Further, although an example in which a file name is added as additional data information has been described, the present invention is not limited to this, and the position of the additional data may be added as additional data information.

  As described above, in this embodiment, an area that may be post-processed by using editing software after shooting, that is, a flat area with a flat brightness such as the sky, and a flat area in the main subject (such as facial skin) ) And the additional data is recorded in association with the reduced range image data. By doing this, the amount of recorded data is reduced as much as possible, and when the tone adjustment is performed on the range-reduced image data, a tone jump occurs and an unnatural image such as a pseudo contour is created. It is possible to prevent.

  In the present embodiment, the image analysis unit 115 uses the face detection / face recognition evaluation value. However, the present invention is not limited to this. For example, the image analysis unit 115 further includes a detection block that detects a subject or an image pattern that is likely to be adjusted by post-processing using an editing software after shooting, and adds the evaluation value calculated in each block. The final post-processing evaluation value may be calculated.

  FIG. 10 shows a modification of the image analysis unit 115. The image analysis unit 115 in FIG. 10 is obtained by further adding a function block to be analyzed to the example of the image analysis unit 115 described in FIG. Therefore, the functional blocks having the same reference numerals as those in FIG. 4 are the same as those described in FIG.

  In FIG. 10, a user setting information acquisition unit 1001 acquires setting information when the user arbitrarily sets a subject to be post-processed using the touch panel of the digital camera 100 or the like. For example, when the user inputs the subject and the importance of post-processing when setting the subject, the higher the importance set by the user, the higher the evaluation value output from the user setting information acquisition unit 1001, and post-processing The post-process evaluation value of the evaluation value calculation unit 403 is calculated to be high. This is because weight is added because it is highly likely that the tone control will be performed again because the image is focused on by the user.

  A memory color detection unit 1002 that detects a memory color detects a memory color such as a sunset or a cherry blossom. For example, the RGB values of the sunset color and cherry blossom color are recorded in the ROM 113 in advance, and the memory color detection unit 1002 indicates that the closer the RGB value of the high gradation image data and the RGB value of the memory color recorded in the ROM 113 are, The evaluation value output from the memory color detection unit 1002 is increased. By doing so, the post-processing evaluation value of the post-processing evaluation value calculation unit 403 is calculated to be high. This is because a weight is added because there is a high possibility that the gradation control is performed again on a portion that is easily memorized and remains in the impression.

  The high-intensity area detection unit 1003 detects a high-intensity part with a high compression rate when the gradation compression unit 206 performs gradation correction. For example, the higher the luminance is, the higher the gradation compression rate in the gradation compression unit 206 is, and the lower bit width to be lost is larger. Therefore, the higher the luminance is, the higher the luminance is output from the high luminance region detection unit 1003. Increase the evaluation value. By doing so, the post-processing evaluation value of the post-processing evaluation value calculation unit 403 is calculated to be high. This is because a weight is added because there is a high possibility that the gradation control is performed again on a portion with high brightness and conspicuous in the data reduced by the gradation compression.

  The exposure step information detection unit 1004 detects the exposure step information of a plurality of predetermined image data input to the image data composition unit 204. For example, the larger the exposure step, the larger the lower bit width that disappears when the tone compression unit 206 performs tone compression. Therefore, the larger the exposure step, the more output from the exposure step information detection unit 1004. Increase the evaluation value. By doing so, the post-processing evaluation value of the post-processing evaluation value calculation unit 403 is calculated to be high.

  The texture area detection unit 1005 detects a texture area having a complicated pattern having many high frequency components. For example, a texture region is detected by extracting a variance value of pixel values from an image and detecting one having a value larger than a predetermined value. Compared with the flat area, the texture area has a feature that even if a pseudo contour is generated by tone jump by gradation compression, even if a pseudo contour is generated because the pattern is complicated, the texture area is not conspicuous. Therefore, the evaluation value output from the texture region detection unit 1005 is increased as the texture pattern is increased. By doing so, the post-processing evaluation value of the post-processing evaluation value calculation unit 403 is calculated to be lower than the previous blocks.

  The post-processing evaluation value calculation unit 403 may be configured to calculate a final post-processing evaluation value from the evaluation values calculated in the respective blocks 1001 to 1005.

  In the present embodiment, for the image having a high post-processing evaluation value, based on the additional data generation table in FIG. However, the present invention is not limited to this. For example, when it is desired to further reduce the amount of additional data, the gradation compression rate is determined according to the luminance value for each pixel from the characteristics used in the gradation compression unit 206, that is, the characteristics of gamma processing, knee processing, and black stretch processing. Is calculated. Then, the post-processing evaluation value may be calculated to be higher as the gradation compression rate is higher from the calculation result, and the lower bit width of the additional data may be controlled for each pixel. In such a case, for the pixel whose post-processing evaluation value is lower than the predetermined value, the additional data may be omitted, or zero-padded so that the bit width is adjusted to all pixels.

(Embodiment 2)
Next, as Embodiment 2, an example in which the present invention is applied when a moving image is captured and moving image data is recorded will be described.

  In the second embodiment, an example in which the present invention is applied to a digital camera as in the first embodiment will be described as an example of an image recording apparatus, and the basic configuration is the same as that in the first embodiment. In the following description, only an operation flowchart, which is a difference from the first embodiment, and a GUI example in post-processing editing software will be described.

  The processing at the time of recording moving image data of the digital camera 100 will be described in detail using the flowchart of FIG. FIG. 11 is an operation flowchart of recording processing according to Embodiment 2 of the present invention. The flowchart of FIG. 11 illustrates a processing procedure executed by controlling each processing block by the control unit 111. The control unit 111 expands a program stored in the memory (ROM) to the memory (RAM). However, this is realized by the execution of the CPU. In the flowchart of FIG. 11, the processes denoted by the same reference numerals as those in FIG. 7 are the same as those in the first embodiment, and thus the description thereof is omitted here.

  In steps S701 to S704, the flow until the post-processing evaluation value is calculated is the same as that described with reference to FIG.

  In step S1101, the post-processing evaluation value calculation unit 403 calculates post-processing evaluation values for a predetermined number of frames based on the detection result of a scene change detection unit (not shown). For example, the post-processing evaluation value calculation unit 403 is configured to use a constant post-processing evaluation value for 30 frames, which is a predetermined period, and shorten the calculation processing time such as additional data generation. In that case, based on the detection result of the scene change detection unit (not shown), the change point of the post-processing evaluation value is made the same as the scene break so that the transition point of the post-processing evaluation value does not become unnatural. The control unit 111 controls.

  In steps S706 to S709, the flow for recording the additional data in association with the reduced range image data is the same as that described with reference to FIG.

  In step S1102, it is determined whether the moving image data to be recorded has been completed. If all moving image data has already been input, the recording process ends. If not, the process moves to S701.

  Next, FIG. 12 shows an example of GUI of editing software when post-processing the recorded moving image data. In FIG. 12, the left side 1201 of the screen shows a file list of moving image data files, and the thumbnails of the recorded moving image data are displayed in the shooting order from top to bottom. The right side 1202 of the screen is a timeline display. In the example of FIG. 12, the file name corresponding to the thumbnail 2 in the file list 1201 is “002. The example in case a user selects MTS is shown. Depending on the final post-processing evaluation value calculated by the post-processing evaluation value calculation unit 403, a scene that is likely to be post-processed is displayed on the timeline with a post-processing necessity level of high (1204, 1210) or a post-processing necessity level: medium. (1207) is an example displayed on the timeline. Accordingly, it is possible to identify on the timeline the presentation of which scene is likely to be edited with editing software at a glance. For a scene with a high post-processing evaluation value, in the image recording apparatus of this embodiment, a large number of lower bits of high gradation data are added as additional data to the range-reduced image data and recorded. Therefore, even if the user adjusts the gradation by post-processing, tone jump does not occur, and it is possible to prevent a pseudo contour from being generated and an unnatural image.

  As described above, the image recording apparatus according to the present embodiment focuses on scenes that may be post-processed when moving image data is post-processed using editing software or the like in addition to the first embodiment. The additional reduced data is associated with the range reduced image data and recorded. This makes it possible to reduce the amount of recording data as much as possible, and to prevent the adverse effect of an unnatural image when tone adjustment is performed on range-reduced image data.

  In the second embodiment, for example, the user may arbitrarily set a subject to be post-processed by using a touch panel or the like at the time of shooting, and may include a user setting information acquisition unit 1001 that acquires the set information. good. In addition, a memory color detection unit 1002 that detects a memory color such as sunset or cherry blossoms, and a high luminance region detection unit 1003 that detects a high luminance part whose compression rate is high when gradation correction is performed in the gradation compression unit 206 are provided. May be. The image processing apparatus further includes blocks such as an exposure step information detection unit 1004 that detects exposure step information of a plurality of predetermined image data input to the image data composition unit 204, a texture region detection unit 1005 that detects a texture region, and the like. good. As described above, the post-processing evaluation value is calculated from each evaluation value calculated in each block in the same manner as described in the first embodiment, and the user should post-process a scene having a high post-processing evaluation value. You may make it the structure to carry out.

  In addition, although it was set as the structure which calculates the post-processing evaluation value for every predetermined | prescribed frame for the moving image data input, it is not restricted to this, for example, it calculates by thinning out the post-processing evaluation value, The evaluation value may be calculated by interpolation.

(Other embodiments)
Furthermore, each process shown in the flowchart in each embodiment described above is executed by the CPU of the system by reading a computer program for realizing the function of each process from the memory of the system in which the image encoding apparatus of the present invention operates. Can also be realized. In this case, the program stored in the memory constitutes the present invention.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  Moreover, you may implement | achieve the function of all or one part of each process shown to the flowchart figure with exclusive hardware. In addition, a program for realizing the function of each process shown in the flowchart diagram is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read into a computer system and executed. May be performed. Here, the “computer system” includes an OS and hardware such as peripheral devices.

  Here, the “computer-readable recording medium” includes a portable medium such as a flexible disk, a magneto-optical disk, a ROM, and a CD-ROM, and a storage device such as a hard disk built in the computer system. Furthermore, a program that holds a program for a certain period of time, such as a volatile memory (RAM) inside a computer system that becomes a server or client when the program is transmitted via a network such as the Internet or a communication line such as a telephone line Shall also be included.

  The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

  A program product such as a computer-readable recording medium in which the above program is recorded can also be applied as an embodiment of the present invention. The above program, recording medium, transmission medium, and program product are included in the scope of the present invention.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope shown in the claims.

DESCRIPTION OF SYMBOLS 101 Optical system 102 Image pick-up element 103 Analog signal processing part 104 A / D conversion part 105 Image processing part 106 Additional data generation part 107 Codec part 108 Recording medium 109 Image display part 111 Control part 112 Operation input part 113 ROM
114 RAM
115 Image analysis unit

Claims (13)

Image signal generating means for generating high gradation image data;
A region detecting unit for detecting a region to be post-processed from the high gradation image data generated by the image signal generating unit;
Calculating means for calculating a post-processing evaluation value of the area detected by the area detecting means;
Range reduction means for gradation-compressing the high gradation image data to generate range reduced image data;
Additional data generation means for generating additional data based on data lost by gradation compression by the range reduction means;
Recording means for associating and recording the range reduced image data generated by the range reduction means and the additional data generated by the additional data generation means;
The image recording apparatus, wherein the additional data generation unit controls a method of generating additional data according to the post-processing evaluation value calculated by the calculation unit. The region detecting means includes
Flat area detecting means for detecting a flat area with a small change in luminance in the high gradation image data;
An area calculating means for calculating the area of the flat area detected by the flat area detecting means,
The image recording apparatus according to claim 1, wherein when the area of the flat area calculated by the area calculating unit is larger than a predetermined ratio, the area is detected as a target area for the post-processing. The calculating means includes
Subject detection means for detecting a main subject in the target area of the post-processing detected by the area detection means;
The image recording apparatus according to claim 1, wherein the post-processing evaluation value is calculated based on a detection result of the subject detection unit.   The image recording apparatus according to claim 3, wherein the calculation unit calculates the post-processing evaluation value using a post-processing evaluation value table.   4. The subject detection means comprises at least one of a face detection means for detecting a human face from the high gradation image data and a face recognition means for recognizing a human face. The image recording apparatus described in 1.   5. The image recording apparatus according to claim 1, wherein the range reduction unit includes a non-linear processing unit that performs at least one of gamma processing, knee processing, and black stretch processing. 6. The calculating means includes
Means for detecting a high brightness area;
Means for detecting a memory color;
Means for detecting an exposure step used in the image signal generating means;
Means for detecting a texture region,
The image recording apparatus according to claim 1, wherein the post-processing evaluation value is increased according to any detection result.   The said additional data production | generation means produces | generates the said additional data with respect to the whole screen including the object area | region of the post-processing detected by the said area | region detection means, The any one of Claim 1 thru | or 7 characterized by the above-mentioned. The image recording apparatus described.   2. The additional data generation unit is characterized in that the additional data is not added to a pixel whose post-processing evaluation value is lower than a predetermined value, or zero-padded and the bit width is adjusted to all pixels. 8. The image recording apparatus according to any one of items 1 to 7. The calculating means includes
Having scene change detection means,
The image recording apparatus according to claim 1, wherein the post-processing evaluation value is calculated according to a scene change detection result detected by the scene change detection unit. An image signal generation step for generating high gradation image data;
A region detecting step of detecting a region to be post-processed from the high gradation image data generated in the image signal generating step;
A calculation step of calculating a post-processing evaluation value of the region detected in the region detection step;
A range reduction process for generating range reduced image data by gradation compressing the high gradation image data;
An additional data generation step of generating additional data based on the data lost by the gradation compression in the range reduction step;
A recording step of associating and recording the range reduced image data generated in the range reduction step and the additional data generated in the additional data generation step;
In the additional data generation step, an additional data generation method is controlled according to the calculated post-processing evaluation value.   The program for making a computer perform each process of the image recording method of Claim 11.   A computer-readable recording medium on which the program according to claim 12 is recorded.

Images