JP2005151090A - Generation of image file including image correction parameter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily generate an image file the image data of which is related to a set of image correction parameters suitable for each image generating apparatus. <P>SOLUTION: Reference image data of a prescribed test chart and object image data generated by imaging a test chart are acquired. A target parameter is selected from a plurality of image correction parameters, comparing the reference image data with the object image data after color space processing determines a target correction parameter, and processing of updating the object image data after color space processing is sequentially performed by the image correction of the determined value as to a plurality of image correction parameters. A plurality of determined image correction parameters are set as a set of image correction parameters suitable for a particular image generating apparatus. The set of the set image correction parameters is stored in the image generating apparatus. The image file including image data generated by the image generating apparatus and the set of the image correction parameters is generated. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to generation of an image file including image correction parameters.

  As a technique for adjusting the output image quality of image data generated by a digital still camera (DSC), digital video camera (DVC), or other image generation device, an image in which an image correction parameter set as image processing information is associated with the image data A technique using a file is known. With this technique, for example, the user designates an arbitrary correction value for each image correction parameter before or after imaging of the image data, thereby associating the image correction parameter set specified for the image data with the image file. Can be generated. When the image data is output, the image data is subjected to output processing after being subjected to image processing (image correction) using the image correction parameter set written in the image file. Accordingly, if an appropriate correction value is designated for each image correction parameter, an appropriate image output result can be obtained.

JP 2002-344881 A JP 2002-344989 A

  However, the image correction parameter set for obtaining an optimal image output result differs depending on the image generation apparatus and the image output apparatus to be used. Further, image correction for obtaining an optimal image output result is generally performed by combining corrections related to a plurality of image correction parameters such as contrast and color balance. Therefore, it is not easy to generate an image file in which an image correction parameter set for obtaining an optimal image output result suitable for each image generation apparatus is associated with image data.

  The present invention has been made to solve the above-described conventional problems, and can easily generate an image file in which an image correction parameter set suitable for each image generation apparatus is associated with image data. The purpose is to provide.

In order to solve the above problems, an image file generation method of the present invention is an image file generation method for generating an image file,
(A) generating an image correction parameter set used when executing specific image correction on image data generated by a specific image generation device;
(B) storing the image correction parameter set in a memory in the specific image generating device;
(C) imaging with the specific image generation device;
(D) generating an image file including the image correction parameter set and the image data generated by the imaging;
With
The step (a)
(I) obtaining reference image data expressed in a reference color space as image data representing a predetermined test chart;
(Ii) obtaining target image data generated by imaging the test chart by the specific image generation device;
(Iii) generating a target image data after color space processing by matching a color space applied to the target image data with the reference color space;
(Iv) setting an image correction parameter set based on the reference image data and the target image data after the color space processing;
With
The step (iv)
Attention correction parameter selection processing for selecting one unselected image correction parameter as a attention correction parameter from among a plurality of image correction parameters;
A parameter value for comparing the reference image data with the target image data after the color space processing and determining a value of the attention correction parameter so that the target image data after the color space processing is adapted to the reference image data The decision process,
Target image correction processing for updating the target image data after the color space processing by performing image correction using the determined value of the correction parameter for attention;
Sequentially executing each of the image correction parameters in the plurality of image correction parameters;
And setting a plurality of image correction parameter values determined in the parameter value determination process as an image correction parameter set suitable for the specific image generation apparatus.

  In this image file generation method, determination of a target correction parameter value that matches target image data generated by a specific image generation device with reference image data, and target image data using the determined target correction parameter value Update by image correction is automatically repeated, a plurality of determined image correction parameter values can be set as an image correction parameter set, and the set image correction parameter set can be stored in the image generation apparatus. The image generation apparatus generates an image file by associating the image correction parameter set with the image data. Thus, according to the present image file generation method, an image file in which an image correction parameter set suitable for each image generation apparatus is associated with the image data can be easily generated.

  In the image file generation method, the reference image data may be image data that has been subjected to image correction to obtain a desired color reproduction when output using a specific output device. The reference image data may be image data that has been subjected to image correction to obtain a desired color reproduction when output to a specific print medium using a specific output device.

  According to this configuration, when image data generated by a specific image generation device is output to a specific print medium in a specific output device, an image correction parameter set of image data for obtaining a desired color reproduction can be easily obtained. Can be generated.

  In the image file generation method, the image correction for obtaining the desired color reproduction may include memory color correction.

  According to this configuration, by performing image correction including memory color correction to generate reference image data, it is possible to easily convert the reference image data into image data whose output result in a specific output device is desirable color reproduction. It can be.

  In the image file generation method, the image correction in the target image correction process may include tone curve correction and memory color correction.

  According to this configuration, it is possible to easily set an image correction parameter set that adapts target image data to reference image data.

  In the image file generation method, the plurality of image correction parameters are the same as the image correction parameters used for the specific image correction, and the selection order of the target correction parameters in the target correction parameter selection process is the specific image. The correction execution order for each image correction parameter in the correction may be the same.

  According to this configuration, the specific image correction is performed in the same order as the attention correction parameter selection order using the same image correction parameters used when generating the image correction parameters. It is possible to generate an image correction parameter set so that the output result of the performed image data provides more desirable color reproduction.

  In the image file generation method, the selection order may be an order of a highlight correction parameter, a brightness correction parameter, a contrast correction parameter, a color balance correction parameter, and a memory color correction parameter.

  Since these image correction parameters have a great influence on the output image quality, if an image correction parameter set is generated using the above selection order for these image correction parameter values, the output result of the image data is reproduced as desired. It is possible to easily set an image correction parameter set that can be

  In the image file generation method, the step (a) includes, for each combination of the image correction parameter set, the specific image generation device and an output device used for outputting image data generated by the specific image generation device. It is good also as a process to produce | generate. In the image file generation method, the step (a) includes using the image correction parameter set for the specific image generation device and an output device for outputting image data generated by the specific image generation device; It is good also as a process produced | generated for every combination with a printing medium.

  According to this configuration, it is possible to generate an image correction parameter set that reflects the characteristics of the image generation device, the output device, and the print medium.

  In the image file generation method, the step (a) may be a step of generating the image correction parameter set for a plurality of shooting scene modes that can be used by the specific image generation apparatus.

  According to this configuration, it is possible to generate an image correction parameter set that is more suitable for the shooting scene mode (shooting target).

In order to solve at least a part of the above problems, the image correction parameter transmission system of the present invention transmits an image correction parameter set for a specific image generation device in the form of an installer file via a network. A parameter transmission system,
A device information acquisition unit that acquires user device information that is a combination of an image generation device and an image output device used by a user via the network;
An installer file transmitting unit that transmits an installer file including at least one image correction parameter set suitable for the combination and an installation program for the image correction parameter set to the user based on the user device information;
With
The installer file has a function of storing the image correction parameter set in a memory in an image generation apparatus used by the user by an execution operation of the installation program.

  In this image correction parameter transmission system, acquisition of device information used by a user and transmission of an image correction parameter set suitable for the device can be performed easily and quickly via a network. In addition, since the user acquires the image correction parameter set in the installer file format, the image correction parameter set can be easily stored in the device used by the user.

  It should be noted that the present invention can be realized in various modes, for example, an image file generation method and apparatus, an image data processing method and apparatus, a computer program for realizing the functions of these methods or apparatuses, and the like The present invention can be realized in the form of a recording medium that records a computer program, a data signal that includes the computer program and is embodied in a carrier wave, and the like.

Next, embodiments of the present invention will be described in the following order based on examples.
A. Image processing system configuration:
B. Reference image data generation processing:
C. Image correction parameter generation processing:
D. Image file structure:
E. Image correction parameter set delivery:
F. First Example of Image File Generation Processing Using Image Correction Parameter Set:
G. Image output processing:
H. Second Embodiment of Image File Generation Processing Using Image Correction Parameter Set:
I. Variation:

A. Image processing system configuration:
FIG. 1 is an explanatory diagram showing an example of the configuration of an image processing system 10 as an embodiment of the present invention. The image processing system 10 generates an image correction parameter generation system 20 that generates an image correction parameter set, generates an image file that can use the image correction parameter set, and generates an image file that performs image output processing using the image correction parameter set. An output system 30 is provided.

  The image correction parameter generation system 20 generates an image correction parameter set by using a digital still camera 40 as an image generation apparatus that generates image data, a printer 50 as an image output apparatus that outputs image data, and the image data. And a computer 60 as an image correction parameter generation device.

  A computer 60 as an image correction parameter generation device includes a reference image generation unit 62 that generates reference image data, and an image correction parameter generation unit 64 that generates an image correction parameter set. The image correction parameter generation unit 64 includes a reference image storage unit 641, a target image storage unit 642, a color space processing unit 643, and a parameter value setting unit 644. The functions of these parts will be described later.

  The image file generation / output system 30 includes a digital still camera 70 as an image file generation device that generates an image file, a printer 80 as an image output device, and a personal computer PC as an image processing device. The printer 80 as an image output device may include an image processing unit 82 that performs image processing of image data. The functions of these parts will be described later.

  The digital still camera 40 of the image correction parameter generation system 20 and the digital still camera 70 of the image file generation / output system 30 have the same image generation characteristics, and usually the same model is used. Further, the printer 50 of the image correction parameter generation system 20 and the printer 80 of the image file generation / output system 30 have the same image output characteristics, and usually the same model is used. An arbitrary digital still camera can be used for reference image data generation processing in the image correction parameter generation system 20 described later.

B. Reference image data generation processing:
FIG. 2 is a flowchart showing an example of the generation process of the reference image data TGD in the image correction parameter generation system 20. In step S100, reference / standard image data RTGD (see FIG. 2) is generated by capturing a test chart and a reference image with an arbitrary digital still camera DSC. A test chart of a color patch is used as the test chart, and the color patch includes a gray scale patch, other color patches, a memory color patch, and the like. Further, any image can be selected as the reference image. For example, a person image, a landscape image, or the like can be selected.

  In step S110, the reference / standard image data RTGD generated in step S100 is output by a specific printer 50 to a specific print medium (for example, dedicated glossy paper or matte paper).

  In step S120, the operator determines whether or not the reference image portion of the output result of the reference / standard image data RTGD output in step S110 has a desired color reproduction. As a result, when it is determined that the color reproduction is not desirable (step S120: No), the process proceeds to step S130.

  In step S130, the operator corrects the reference / standard image data RTGD used for output in step S110. The correction processing of the reference / standard image data RTGD is executed so that the reference image portion of the output result in step S110 has a desired color reproduction. The correction processing of the reference / standard image data RTGD can be performed by using the arbitrary correction method in the standard image generation device 62 of the computer 60, for example, for contrast, color balance, memory color, and the like. The correction can be performed using a general correction processing method such as tone curve correction or memory color correction. The correction process performed in step S130 is referred to as “reference correction”. In step S130, after the reference / standard image data RTGD correction process is executed, the process returns to step S110 again.

  On the other hand, if it is determined in step S120 that the color reproduction is desirable (step S120: Yes), the process proceeds to step S140. In step S140, only the image data of the test chart portion is extracted from the reference / standard image data RTGD and set as standard image data TGD.

  As described above, the reference image data TGD is image data obtained by performing reference correction on the test chart image generated by the digital still camera DSC. The standard correction is an image correction of image data such that an output result obtained by outputting a certain image (reference image) to a specific print medium by a specific printer 50 achieves a desired color reproduction.

  The output result of the image data is different for each printer to be used or for each combination of the printer and the print medium. Therefore, it is preferable that the reference image data TGD is generated for each target printer or for each combination of the target printer and the print medium. In addition, the desirability of color reproduction of the output result of the image data varies depending on the shooting scene mode (shooting target) of the image data. Therefore, it is preferable that the standard image data TGD is generated for each reference image to be selected (that is, for each shooting scene mode).

  The generated reference image data TGD is stored in the reference image storage unit 641 of the image correction parameter generation unit 64 of the computer 60.

C. Image correction parameter generation processing:
FIG. 3 is a flowchart showing a processing routine of image correction parameter generation processing in the computer 60 (FIG. 1) as the image correction parameter generation device. In step S200, the color space processing unit 643 acquires the reference image data TGD from the reference image storage unit 641 of the image correction parameter generation unit 64 and the target image data OGD from the target image storage unit 642, respectively. The target image data OGD is test chart image data obtained by capturing the same test chart as that used when generating the reference image data with a specific digital still camera 40.

  In step S210, the color space processing unit 643 performs a color space conversion process that matches the color space applied to the target image data OGD with the color space of the reference image data TGD. The color space conversion process can be performed using, for example, a color space conversion matrix. By the color space conversion process, the target image data OGD and the reference image data TGD become image data expressed in the same color space. Various color spaces exist in the color space of the image data. In this embodiment, the color space of the reference image data TGD is a special RGB color space for image correction (hereinafter referred to as “cRGB color space”). It will be explained as being.

  In step S220, the parameter value setting unit 644 performs comparison / correction processing using the reference image data TGD and the target image data OGD that has undergone the color space conversion processing in step S210. In the comparison / correction processing, the image data of the reference image data TGD and the target image data OGD are compared, image correction parameter values that match the target image data OGD with the reference image data TGD are determined, and the determined parameter values The target image data OGD is updated by performing image correction using. Such processing is sequentially executed for a plurality of image correction parameters. As the image correction parameters, highlight correction parameters, brightness correction parameters, contrast correction parameters, color balance correction parameters, memory color correction parameters, and the like can be used. The comparison / correction process will be described in detail later.

  In step S230, the parameter value setting unit 644 sets an image correction parameter set. The image correction parameter set is set by setting a plurality of image correction parameter values determined in the comparison / correction processing in step S220 as an image correction parameter set.

  By performing the above processing, the computer 60 as the image correction parameter generation device can generate an image correction parameter set.

  FIG. 4 is a flowchart showing a processing routine of comparison / correction processing (step S220 in FIG. 3) in the present embodiment. In step S300, the parameter value setting unit 644 of the image correction parameter generation unit 64 selects the highlight as a target correction parameter, and the target image data OGD and the reference image data subjected to the color space conversion process (step S210 in FIG. 3). The highlight correction parameter value is determined by comparing with TGD. The comparison between the target image data OGD and the reference image data TGD is performed on the highlighted patch portion (white patch) of both image data. The determination of the highlight correction parameter value is to obtain a correction value that best matches the target image data OGD that has undergone highlight correction using a certain correction value and the reference image data TGD in the highlight patch portion. To do.

  As an index value representing the degree of matching between image data, for example, a square sum of errors between image data can be used. Therefore, when obtaining the highlight correction value, the average value of the pixel values of the white patch of the reference image data TGD and the average value of the pixel values of the white patch of the target image data OGD are obtained, and the difference between the two average values is obtained. This is an error between image data of each patch. When a plurality of white patches are included in the test chart, an error between the image data for each white patch is obtained, and a square sum of the errors between the image data is obtained. The square sum of the error between the image data is obtained for each of the R signal, the G signal, and the B signal. The highlight correction value is determined so that the sum of the square sum of the errors between the image data for each of these signals is minimized.

  For example, highlight correction of image data can be performed by tone curve correction as shown in FIG. In the example of FIG. 5, a correction tone curve (TC1 or TC2) is created by designating a highlight correction value (for example, Ch1 or Ch2) for the tone curve TC0 before correction. By applying this correction tone curve to the target image data OGD, highlight correction of the target image data OGD can be performed. In this example, the same tone curve is commonly applied to each RGB color.

  In step S310, the parameter value setting unit 644 performs highlight correction on the target image data OGD that has undergone the color space conversion process, using the highlight correction parameter value determined in step S300. The target image data OGDa after the highlight correction is used as target image data when determining the next image correction parameter value.

  In step S320, the parameter value setting unit 644 selects brightness as the attention correction parameter, compares the target image data OGDa after highlight correction in step S310 with the reference image data TGD, and determines the brightness correction parameter value. To decide. The comparison between the target image data OGDa and the reference image data TGD is performed for the gray scale patch portions of both image data.

  The brightness correction parameter value is determined by obtaining a correction value that best matches the target image data OGDa that has undergone brightness correction using a certain correction value and the reference image data TGD in the gray scale portion. Do. Specifically, since there are a plurality of gray scale patches, the sum of the square sum of the errors between the target image data OGDa subjected to brightness correction and the reference image data TGD is minimized with respect to the plurality of patches. As described above, the brightness correction parameter value is determined.

  The brightness correction of the image data can be performed by, for example, tone curve correction as shown in FIG. In the example of FIG. 6, TC0 represents a tone curve before correction. The brightness correction value can be represented by an output level adjustment amount (for example, Cb1 or Cb2) at an arbitrary reference input level (for example, Iref1 or Iref2). That is, the output level corresponding to the corrected reference input level is a value obtained by increasing or decreasing the output level adjustment amount (correction value) from the output level value corresponding to the reference input level before correction. A correction tone curve (TC1 or TC2) is created by interpolating an output level corresponding to an input level other than the reference input level with a spline function. By applying this correction tone curve to the target image data OGDa, brightness correction can be performed. In this example, the same tone curve is commonly applied to each RGB color.

  In step S330, the parameter value setting unit 644 performs brightness correction on the target image data OGDa after the highlight correction in step S310, using the brightness correction parameter value determined in step S320.

  In step S340, the parameter value setting unit 644 selects contrast as the attention correction parameter, compares the target image data OGDb after the brightness correction in step S330 with the reference image data TGD, and determines the contrast correction parameter value. To do. The comparison between the target image data OGDb and the reference image data TGD is performed for the gray scale patch portions of both image data.

  The contrast correction parameter value is determined by obtaining a correction value that best matches the target image data OGDb subjected to contrast correction using a certain correction value and the reference image data TGD in the gray scale portion. Specifically, since there are a plurality of patches of gray scale, the sum of the square sum of errors between the target image data OGDb subjected to contrast correction and the reference image data TGD is minimized with respect to the plurality of patches. In addition, a contrast correction parameter value is determined.

  The contrast correction of the image data can be performed by, for example, tone curve correction as shown in FIG. In the example of FIG. 7, TC0 represents a tone curve before correction. The contrast correction value can be expressed by an output level adjustment amount (for example, Cc1 and Cc1 'or Cc2 and Cc2') at an arbitrary reference input level (for example, Iref and Iref '). The output level corresponding to the corrected main reference input level (Iref) is a value obtained by performing adjustment to increase or decrease the output level adjustment amount (correction value) with respect to the output level value corresponding to the main reference input level before correction. To do. The output level corresponding to the corrected secondary reference input level (Iref ′) is opposite to the sign of the adjustment amount (correction value) in the primary reference input level with respect to the output level value corresponding to the secondary reference input level before correction. The value adjusted according to the adjusted amount is used. A correction tone curve (TC1 or TC2) is created by interpolating an output level corresponding to an input level other than the reference input level with a spline function. By applying this correction tone curve to the target image data OGDb, contrast correction can be performed. In this example, the same tone curve is commonly applied to each RGB color.

  In step S350, the parameter value setting unit 644 performs contrast correction on the target image data OGDb after the brightness correction in step S330, using the contrast correction parameter value determined in step S340.

  In step S360, the parameter value setting unit 644 selects color balance as the attention correction parameter, compares the target image data OGDc after contrast correction in step S350 with the reference image data TGD, and sets the color balance correction parameter value. decide. The comparison between the target image data OGDc and the reference image data TGD is performed for the color patch portions of both image data.

  The color balance correction parameter value is determined by obtaining a correction value that best matches the target image data OGDc subjected to color balance correction using a certain correction value and the reference image data TGD in the color patch portion. . The color balance correction parameter value is determined for each color signal in accordance with the color space applied to the image data. In this embodiment, the determination is made for each of the R signal, the G signal, and the B signal. Specifically, since there are a plurality of color patches, the sum of squares of errors between the target image data OGDc subjected to the color balance correction and the reference image data TGD is minimized for each of the RGB colors. Thus, the color balance correction parameter values for RGB are determined.

  The color balance correction of the image data can be performed, for example, by tone curve correction as shown in FIG. FIG. 8 shows an example of tone curve correction for the R signal. TC0 represents a tone curve before correction. The color balance correction value can be represented by an output level adjustment amount (for example, Cr1 or Cr2) at an arbitrary reference input level (for example, Iref). That is, the output level corresponding to the corrected reference input level is a value obtained by increasing or decreasing the output level adjustment amount (correction value) from the output level value corresponding to the reference input level before correction. A correction tone curve (TC1 or TC2) is created by interpolating an output level corresponding to an input level other than the reference input level with a spline function. By applying this correction tone curve to the target image data OGD, color balance correction for the R signal can be performed. Color balance correction can be similarly performed for the G signal and the B signal.

  In step S370, the parameter value setting unit 644 performs color balance correction on the target image data OGDc after the contrast correction in step S350, using the color balance correction parameter value determined in step S360.

  In step S380, the parameter value setting unit 644 selects the memory color as the attention correction parameter, compares the target image data OGDd after color balance correction in step S370 with the reference image data TGD, and stores the memory color correction parameter value. To decide. The memory color refers to a color of an area that is easily noticed by a person, and includes, for example, a skin color area, a green area, and a blue area. The comparison between the target image data OGDd and the reference image data TGD is performed for a patch portion in a color range of a certain memory color (hereinafter referred to as a memory color range) of both image data.

  The memory color correction parameter value is determined by determining a correction value that best matches the target image data OGDd subjected to the memory color correction using a certain correction value and the reference image data TGD in the patch portion within the memory color range. Do it by asking. The memory color correction parameter value is determined for each memory color. Further, each memory color is performed for each color signal in accordance with the color space applied to the image data. In this embodiment, the determination is made for each of the R signal, the G signal, and the B signal. Specifically, regarding a patch within a memory color range of a certain memory color, the sum of squares of errors between the target image data OGDc subjected to memory color correction and the reference image data TGD is minimized for each of the RGB colors. In addition, the memory color correction parameter value for each RGB of a certain memory color is determined.

  The memory color correction of the image data can be performed by, for example, memory color correction as shown in FIG. FIG. 9 shows an example of memory color correction for image data within a certain memory color range. The memory color correction is performed for each of the R signal, the G signal, and the B signal. TC0r, TC0g, and TC0b represent tone curves before correction. The memory color correction value can be represented by an output level adjustment amount (for example, Cmr, Cmg, Cmb) at an arbitrary reference input level (for example, Iref). That is, the output level corresponding to the corrected reference input level is a value obtained by increasing or decreasing the output level adjustment amount (correction value) from the output level value corresponding to the reference input level before correction. A correction tone curve (TC1r, TC1g, TC1b) is created by interpolating an output level corresponding to an input level other than the reference input level with a spline function. By applying this correction tone curve to the image data within the memory color range in the target image data OGDd, the memory color correction for the memory color can be performed.

  In step S390, the parameter value setting unit 644 performs memory color correction on the target image data OGDd after color balance correction in step S370, using the memory color correction parameter value for each memory color determined in step S380. .

  In step S400, the parameter value setting unit 644 compares the target image data OGDe after the memory color correction in step S390 and the reference image data TGD, and determines whether the target image data OGDe satisfies a predetermined condition. . The predetermined condition can be, for example, that the sum of square sums of errors between image data for some or all patches of the test chart is within a predetermined upper limit range. Alternatively, for some or all patches of the test chart, the error between the respective image data can be within a predetermined upper limit value and lower limit value range.

  When it is determined in step S400 that the predetermined condition is not satisfied (step S400: No), the correction processing method and the use correction parameter are corrected, and then the comparison / correction processing is started again, and the comparison / correction processing is performed again. Repeat the correction process. The correction processing method can be corrected, for example, by adding a reference input level point when creating a correction tone curve and creating a more precise tone curve. The correction of the use correction parameter can be performed, for example, by adding a shadow correction parameter to the highlight correction parameter to perform highlight-shadow correction.

  On the other hand, if it is determined in step S400 that the predetermined condition is satisfied (step S400: Yes), the process ends, and the process returns to the image correction parameter generation process routine (FIG. 3).

  As described above, the computer 60 as the image correction parameter generation apparatus automatically determines a plurality of image correction parameter values sequentially using the reference image data TGD and the target image data OGD, and determines the determined plurality of image corrections. Parameter values can be set as an image correction parameter set.

  Thus, the generated image correction parameter set can be used for image correction such that the target image data OGD generated by the specific digital still camera 40 is adapted to the reference image data TGD. As described above, the standard image data TGD is generated so that the output result of the reference image (FIG. 2) on the specific printer 50 to the specific print medium is a desirable color reproduction. Accordingly, image correction (specific image correction) using the generated image correction parameter set is performed on arbitrary image data generated by the specific digital still camera 40, and a specific print medium is specified by the specific printer 50. If desired, the desired color reproduction can be obtained from the output result. That is, according to the image correction parameter generation apparatus of the present embodiment, an image of image data that can obtain a desired output result according to a combination of a specific digital still camera, a specific printer, and a specific print medium. A correction parameter set can be easily generated.

  As described above, the reference image data TGD is generated for each combination of a printer and a print medium used at the time of generation. On the other hand, the target image data OGD is generated for each digital still camera used at the time of generation. Accordingly, the computer 60 as the image correction parameter generation device selects the reference image data TGD and the target image data OGD to be stored, thereby setting an image correction parameter set suitable for any combination of a digital still camera, a printer, and a print medium. Can be generated.

  Further, since the standard image data TGD is also generated for each reference image used at the time of generation, the image correction parameter set can be generated for each reference image. Therefore, for example, an image correction parameter set that can be used in accordance with the shooting scene mode (shooting target) such as a human image correction parameter set or a landscape image correction parameter set can be generated.

  Further, as described above, any digital still camera DSC can be used when generating the reference image data TGD, but the same digital still camera as the specific digital still camera 40 used when generating the target image data OGD. May be used. In this way, an image correction parameter set for obtaining a desired output result can be generated more easily.

D. Image file structure:
FIG. 10 is an explanatory diagram schematically showing an example of the internal configuration of an image file GF that can be used in this embodiment. The image file GF includes an image data storage area 101 for storing image data GD and an image data information storage area 102 for storing image data information GI. The image data GD is stored, for example, in the JPEG format, and the image data information GI is stored, for example, in the TIFF format (a format in which data and data areas are specified using tags). Note that the terms “file structure” and “data structure” in this embodiment mean the file or data structure in a state where the file or data is stored in the storage device.

  The image data information GI is information for designating image processing conditions when performing image processing on the image data GD generated by an image generation device such as a digital still camera. The image data information GI can include image correction parameter set information generated by the above-described processing in addition to shooting information such as shooting date and time, aperture, and shutter speed.

  The image file GF according to the present embodiment basically has only the image data storage area 101 and the image data information storage area 102 described above, and has a file structure in accordance with an already standardized file format. be able to. The case where the image file GF according to the present embodiment is adapted to a standardized file format will be specifically described below.

  The image file GF according to the present embodiment can have a file structure in accordance with, for example, a digital still camera image file format standard (Exif). Exif file specifications are defined by the Japan Electronics and Information Technology Industries Association (JEITA). The Exif file format includes a JPEG image data storage area for storing JPEG image data and an attached information storage area for storing various information related to the stored JPEG image data, as in the conceptual diagram shown in FIG. And. The JPEG image data storage area corresponds to the image data storage area 101 in FIG. 10, and the attached information storage area corresponds to the image data information storage area 102 in FIG. That is, image data information GI such as shooting information and image correction parameters is stored in the attached information storage area. As is well known to those skilled in the art, in an Exif file format file, tags are used to identify each data, and each data may be called by a tag name.

  FIG. 11 is an explanatory diagram showing an example of the data structure of the attached information storage area of the image file GF that can be used in this embodiment. As shown in the figure, correction value data relating to image correction parameters such as highlight, brightness, contrast, color balance, and memory color is stored in the attached information storage area according to a specified address or offset value as image data information GI. ing. The additional information storage area can contain a larger number of data, but is not shown in FIG. On the output device side, the image data information GI can be acquired by designating an address or an offset value corresponding to desired information (parameter). Note that the image data information GI can be stored, for example, in an undefined area in the attached information storage area and in a user-defined area released to the user.

E. Image correction parameter set delivery:
The image correction parameter set generated in the image correction parameter generation system 20 (FIG. 1) is sent to the image file generation / output system 30 and used. The image correction parameter set is transmitted from the image correction parameter generation system 20 to the image file generation / output system 30 via a network such as the Internet, or via a cable or a memory card.

  The creator of the image correction parameter set can generate the image correction parameter set in advance and provide it to the user using the system shown in FIG. The image correction parameter set is generated for each combination of a digital still camera, a printer, and a print medium. The image correction parameter set is also generated for each shooting scene mode (shooting target). The image correction parameter set is provided, for example, on a homepage operated by the image correction parameter set generator.

  The user of the image correction parameter set operates, for example, the computer PC to select a desired set from the image correction parameter sets provided on the homepage operated by the image correction parameter set generator. The image correction parameter set can be acquired via

  Alternatively, the creator of the image correction parameter set can generate the image correction parameter set in response to a request from the user and provide it to the user. For example, the user operates the computer PC to display information such as a combination of a digital still camera to be used, a printer, and a print medium, and a shooting scene mode (shooting target) on a homepage operated by the image correction parameter set generator. Specify and send the information over the network. The creator of the image correction parameter set generates an image correction parameter set according to the combination thereof, and transmits the generated image correction parameter set to the user via the network. Even in this way, the user can acquire the image correction parameter set.

  The image correction parameter set is provided to the user in the form of an installation file, for example. FIG. 12 is an explanatory diagram schematically showing an example of the configuration of the installation file IF used in the present embodiment. In the example of FIG. 12, the installation file IF is generated for each combination of a digital still camera and a printer. The installation file IF stores one or a plurality of image correction parameter sets PS corresponding to the combination of the print medium and the shooting scene mode, and an installation program IP for installing the image correction parameter set. By executing the installation program IP on the digital still camera 70 or the computer PC, the image correction parameter set PS is stored in the digital still camera 70 or the computer PC in a predetermined data format. A method of using the image correction parameter set in the digital still camera 70 and the computer PC will be described later.

F. First Example of Image File Generation Processing Using Image Correction Parameter Set:
The digital still camera 70 of the image file generation / output system 30 can acquire the image correction parameter set generated in the image correction parameter generation system 20 by the method described above. The digital still camera 70 can generate an image file having the above-described configuration using the acquired image correction parameter set. FIG. 13 is a block diagram showing a schematic configuration of a digital still camera 70 as an image file generation device. The digital still camera 70 is a camera that electrically records a still image by forming an image on a charge coupled device (CCD) through an optical lens.

  The digital still camera 70 has an optical circuit 71 having a CCD for converting an optical signal into an electric signal, an image acquisition circuit 72 for acquiring an image by controlling the optical circuit 71, and processing the acquired image data. Image processing circuit 73 and a control circuit 74 for controlling each of these circuits. The digital still camera 70 further includes a slot 75 that accommodates the memory card MC, a selection / determination button 76 as a user interface, and a liquid crystal display 77 that is used as a preview of a captured image and a user interface. The control circuit 74 includes a memory (not shown).

  FIG. 14 is a flowchart showing the processing routine of the image file generation processing in the present embodiment. In step S500, the user of the digital still camera 70 acquires one or a plurality of image correction parameter sets suitable for the combination of the digital still camera 70, the printer 80, the print medium, and the shooting scene mode to be used. 70 in a usable state in the control circuit 74 (FIG. 13). For example, as described above, the user can acquire the image correction parameter set in the form of the installation file IF (FIG. 12). By executing the installation program IP in the installation file IF on the digital still camera 70 or on the computer PC connected to the digital still camera 70, the image correction parameter set stored in the installation file IF is The information is stored in a non-volatile memory (not shown) of the control circuit 74 of the digital still camera 70 so as to be usable. The usable state is a state in which the use setting of the image correction parameter set can be performed by operating the selection / determination button 76, for example.

  In step S510, the user sets a shooting mode. The setting of the shooting mode includes the use setting of the image correction parameter set. The use setting of the image correction parameter set is set as to whether or not to use the image correction parameter set stored in the control circuit 74, and when a plurality of image correction parameter sets are stored, which image correction parameter set is selected. The setting of whether to use is included. The use setting of the image correction parameter set can be performed by the user operating the selection / determination button 76 while viewing the display on the liquid crystal display 77 of the digital still camera 70. In a state where user settings are not made (initial setting state), one image correction parameter set is automatically selected according to the shooting scene mode (for example, portrait mode or landscape mode) of the digital still camera 70. It may be done.

  In step S520, the control circuit 74 generates image data GD. The generation of the image data GD is performed in response to a user's photographing request, for example, pressing the shutter. In general, the image data GD is converted into a JPEG format suitable for storing a photographic image and stored. However, other storage formats such as a TIFF format, a GIF format, a BMP format, and a RAW data format may be used. it can.

  In step S530, the control circuit 74 adds the image data information GI to the image data GD to generate an image file GF. When the setting for using the image correction parameter set is made in the setting of the shooting mode, the image file GF including the image correction parameter set information in the image data information GI is generated.

  In step S540, the control circuit 74 can add or change the contents of the image data information GI in the image file GF generated in step S530. The addition / change processing of the image data information GI is performed according to a user setting operation. By adding / changing the image data information GI, for example, the image data information GI including the image correction parameter set is added to the image file GF, or the image correction parameters already included in the image data information GI in the image file GF. The set can be changed to another image correction parameter set. The user setting operation can be performed by the user operating the selection / determination button 76 while viewing the display on the liquid crystal display 77.

  As described above, the image file GF in which the image data information GI including the image correction parameter set is associated with the image data GD is generated.

G. Image output processing:
FIG. 15 is a processing routine of the output process of the image file GF in which the image data GI including the image correction parameter set is associated with the image data GD in the printer 80 (FIG. 1) of the image file generation / output system 30 of the present embodiment. It is a flowchart which shows an example. In step S600, the printer 80 reads the image file GF sent from the digital still camera 70.

  In step S610, the printer 80 retrieves the image data information GI from the attached information storage area of the image file GF, and acquires the image data information GI (step S620).

  In step S630, the image processing unit 82 of the printer 80 analyzes the acquired image data information GI, and executes image processing of the image data GD based on the analyzed image data information GI. If the image data information GI includes an image correction parameter set, image correction (specific image correction) of the image data GD using the image correction parameter set is executed in this image processing. The image correction of the image data GD can be performed by the same method as the image correction executed when the image correction parameter generation apparatus generates the image correction parameter set. That is, color conversion to a color space for image correction (cRGB color space), tone curve correction using the image correction parameter value for each image correction parameter, memory color correction, and the like are performed on the image data GD.

  In step S640, the printer 80 outputs the processed image data GD and ends this processing routine.

  Through the above output processing, the image data GD can be output with desirable color reproduction. Note that the image correction of the image data GD in step S630 is preferably performed in the same order as the attention correction parameter selection order at the time of image correction parameter set generation in the image correction parameter generation apparatus. In this way, a more desirable output result can be obtained.

H. Second Embodiment of Image File Generation Processing Using Image Correction Parameter Set:
FIG. 16 is an explanatory diagram showing an example of an image file generation / output system 30B according to the second embodiment of the present invention. The image file generation / output system 30B includes a digital still camera 70 as an image file generation device that generates an image file GF, a printer 80 as an image output device, and a computer 90 as an image processing device. In the present embodiment, the above-described image file generation processing is that the computer 90 executes the function of acquiring the image correction parameter set and the function of storing the acquired image correction parameter set in the attached information storage area of the image file GF. This is different from the first embodiment (FIG. 1).

  The computer 90 includes an image processing unit 94 that executes image processing of an image file or the like. The image processing unit 94 includes a parameter storage unit 941 that stores an image correction parameter set, an image file storage unit 942 that stores an image file GF, and an image file change processing unit 943 that performs a change process on the image file GF. Yes.

  FIG. 17 is a flowchart showing a processing routine of image processing in the computer 90 as the image processing apparatus. In step S700, the user acquires one or a plurality of image correction parameter sets suitable for the combination of the digital still camera 70, the printer 80, the print medium, and the shooting scene mode to be used, and the parameter storage unit of the image processing unit 94 941 is stored. For example, as described above, the user can acquire the image correction parameter set in the form of the installation file IF (FIG. 12). By executing the installation program IP in the installation file IF on the computer 90, the image correction parameter set is stored in the parameter storage unit 941 of the image processing unit 94.

  In step S 710, the user acquires the image file GF generated by the digital still camera 70 and stores it in the image file storage unit 942 of the image processing unit 94.

  In step S720, the image file change processing unit 943 of the image processing unit 94 changes the image file GF (FIG. 10) stored in step S710 using the image correction parameter set stored in step S700. In the change process of the image file GF, the image file change processing unit 943, when the stored image file GF does not include the image data information GI, the image data information GI including the image correction parameter set stored in the image file GF. Can be added. In addition, when the image correction parameter set is not included in the stored image data information GI of the image file GF, the image correction parameter set stored in the image data information GI of the image file GF is added. Processing can be performed. When the image correction parameter set is included in the image data information GI of the stored image file GF, the image correction parameter set stored in the image data information GI of the image file GF is stored. Processing to rewrite the parameter set can be performed.

  In the change process of the image file GF, the digital still camera 70 used for generating the image file GF, the printer 80 used for output, the print medium, the image file, from the image correction parameter set stored in the parameter storage unit 941. The user selects a set suitable for the combination with the shooting scene mode at the time of generation.

  When the file format of the image file GF is the aforementioned Exif file format, the image file GF includes information on the model used to generate the image file GF. Therefore, the image file change processing unit 943 refers to the model information in the image file GF, automatically selects an image correction parameter set suitable for the model from the parameter storage unit 941, and uses the set to use the image file. GF change processing can also be performed.

  The image file GF in which the image data information GI including the image correction parameter set is associated with the image data GD is also generated by the image processing as described above.

  The image file GF generated in the present embodiment can be output by the above-described image output process (FIG. 15), and the image data GD can be output by a desired color reproduction.

  In this embodiment, the image file change processing unit 943 of the image processing unit 94 may perform image processing (from step S600 to step S630 in FIG. 15) based on the image data information GI of the image file GF. it can. In this case, the image file change processing unit 943 performs image processing including image correction of the image data GD using the image correction parameter set, and the image processed image data GD is sent to the printer 80 and output. The Also, in this case, the image file change processing unit 943 does not add the image correction parameter set stored in the parameter storage unit 941 to the image file GF, but uses the image correction parameter set and the image of the image file GF. Processing can also be performed.

I. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

I1. Modification 1:
In the above embodiment, the image correction parameters used for the comparison / correction processing (step S220 in FIG. 3) in the image correction parameter generation unit 64 are the highlight correction parameter, the brightness correction parameter, the contrast correction parameter, the color balance correction parameter, and the storage. Although the color correction parameters are used, other image correction parameters can be used. As other image correction parameters, for example, a shadow correction parameter, a saturation correction parameter, a sharpness correction parameter, or the like can be used.

  In addition, the selection order of the image correction parameters as the attention correction parameters in the comparison / correction processing can be set to an arbitrary order. However, it is preferable that the order of selecting the target correction parameters is the same as the correction execution order for each image correction parameter in the image correction (specific image correction) of the image data using the image correction parameter set. In this way, the output result of the image data after the specific image correction can be made a more desirable color reproduction.

I2. Modification 2:
In the above embodiment, the skin color area, the green area, and the blue area are given as examples of the memory color, but the color of any other area such as a red area can be set as the memory color.

I3. Modification 3:
In the above-described embodiment, an example of a correction method for each image correction parameter has been described, but other correction methods may be used. For example, the position and number for setting the reference input level point when creating the correction tone curve can be arbitrarily changed.

I4. Modification 4:
In the above embodiment, the reference image data is image data that has been subjected to image correction so that the output result from a specific output device is a desirable color reproduction. However, the reference image data is a color reproduction that is faithful to the imaging target. The image data may be subjected to various image corrections. In this way, the image correction parameter generation apparatus of the present embodiment can generate an image correction parameter set of image data such that the output result is color reproduction faithful to the imaging target.

I5. Modification 5:
In the above embodiment, the digital still camera is used as the image generating apparatus. However, a scanner, a digital video camera, or the like can be used.

I6. Modification 6:
In the above embodiment, a printer is used as the output device. However, the present invention can be applied to the case where a monitor or other device capable of displaying an image such as a CRT display or an LCD display is used as the output device.

I7. Modification 7:
In the above embodiment, the Exif format file has been described as a specific example of the image file, but the format of the image file in the present invention is not limited to this. That is, any image file including image data generated by the image generation apparatus and image data information GI may be used. With such a file, the image data generated by the image generation device can be output with a preferable color reproduction by the output device.

I8. Modification 8:
In the above embodiment, the case where the image data and the image data information GI are included in the same image file has been described as an example. However, the image data and the image data information GI need not necessarily be stored in the same file. Absent. That is, it is only necessary that the image data GD and the image data information GI are associated. For example, association data that associates the image data GD and the image data information GI is generated, and one or a plurality of image data and the image data information GI are generated. May be stored in independent files, and the image data information GI associated with processing the image data GD may be referred to. In such a case, the image data GD and the image data information GI are stored in separate files, but at the time of image processing using the image data information GI, the image data GD and the image data information GI are inseparable. This is because they function in the same way as when they are stored in the same file in practice. That is, an aspect in which the image data GD and the image data information GI are associated at least at the time of image processing is included in the image file GF in the present embodiment. Furthermore, a moving image file stored in an optical disc medium such as a CD-ROM, a CD-R, a DVD-ROM, a DVD-RAM is also included.

  When some or all of the functions of the present invention are realized by software, the software (computer program) can be provided in a form stored in a computer-readable recording medium. In the present invention, the “computer-readable recording medium” is not limited to a portable recording medium such as a flexible disk or a CD-ROM, but an internal storage device in a computer such as various RAMs and ROMs, a hard disk, and the like. An external storage device fixed to the computer is also included.

1 is an explanatory diagram illustrating an example of a configuration of an image processing system 10 as an embodiment of the present invention. 5 is a flowchart showing an example of processing for generating reference image data TGD in the image correction parameter generation system 20. The flowchart which shows the processing routine of the image correction parameter generation process in the computer 60 as an image correction parameter generation apparatus. The flowchart which shows the processing routine of the comparison / correction process in a present Example. Explanatory drawing which shows an example of a highlight correction process. Explanatory drawing which shows an example of a brightness correction process. Explanatory drawing which shows an example of a contrast correction process. Explanatory drawing which shows an example of a color balance correction process. Explanatory drawing which shows an example of a memory color correction process. Explanatory drawing which shows schematically an example of the internal structure of the image file GF which can be used in a present Example. Explanatory drawing which shows an example of the data structure of the attached information storage area of the image file GF which can be used for a present Example. Explanatory drawing which shows schematically an example of a structure of the installation file IF used in a present Example. 1 is a block diagram showing a schematic configuration of a digital still camera 70 as an image file generation device. The flowchart which shows the process routine of the image file production | generation process in a present Example. 9 is a flowchart illustrating an example of a processing routine of an output process of an image file GF in which image data information GI including an image correction parameter set is associated with image data GD in the printer 80 of the image file generation / output system 30 of the present embodiment. Explanatory drawing which shows an example of the image file production | generation / output system 30B in 2nd Example of this invention. The flowchart which shows the process routine of the image process in the computer 90 as an image processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Image processing system 20 ... Image correction parameter generation system 30 ... Image file generation / output system 30B ... Image file generation / output system 40 ... Digital still camera 50 ... Printer 60 ... Computer 62 ... Reference | standard image generation part 64 ... Image correction parameter Generation unit 70 ... Digital still camera 70B ... Digital still camera 71 ... Optical circuit 72 ... Image acquisition circuit 73 ... Image processing circuit 74 ... Control circuit 75 ... Slot 76 ... Determination button 77 ... Liquid crystal display 80 ... Printer 80B ... Printer 82 ... Image Processing unit 90 ... Computer 94 ... Image processing unit 101 ... Image data storage area 102 ... Image data information storage area 641 ... Reference image storage part 642 ... Target image storage part 643 ... Color space processing part 644 ... Parameter value setting part 94 ... parameter storage unit 942 ... image file storage unit 943 ... image file change processing unit

Claims (12)

An image file generation method for generating an image file,
(A) generating an image correction parameter set used when executing specific image correction on image data generated by a specific image generation device;
(B) storing the image correction parameter set in a memory in the specific image generating device;
(C) imaging with the specific image generation device;
(D) generating an image file including the image correction parameter set and the image data generated by the imaging;
With
The step (a)
(I) obtaining reference image data expressed in a reference color space as image data representing a predetermined test chart;
(Ii) obtaining target image data generated by imaging the test chart by the specific image generation device;
(Iii) generating a target image data after color space processing by matching a color space applied to the target image data with the reference color space;
(Iv) setting an image correction parameter set based on the reference image data and the target image data after the color space processing;
With
The step (iv)
Attention correction parameter selection processing for selecting one unselected image correction parameter as a attention correction parameter from among a plurality of image correction parameters;
A parameter value for comparing the reference image data with the target image data after the color space processing and determining a value of the attention correction parameter so that the target image data after the color space processing is adapted to the reference image data The decision process,
Target image correction processing for updating the target image data after the color space processing by performing image correction using the determined value of the correction parameter for attention;
Sequentially executing each of the image correction parameters in the plurality of image correction parameters;
Setting a plurality of image correction parameter values determined in the parameter value determination process as an image correction parameter set suitable for the specific image generation device;
An image file generation method comprising: The image file generation method according to claim 1,
The image file generation method, wherein the reference image data is image data that has been subjected to image correction to obtain a desired color reproduction when output using a specific output device. The image file generation method according to claim 1,
The image file generation method, wherein the reference image data is image data subjected to image correction for obtaining a desired color reproduction when output to a specific print medium using a specific output device. An image file generation method according to claim 2 or claim 3, wherein
The image file generation method, wherein the image correction for obtaining the desired color reproduction includes memory color correction. An image file generation method according to any one of claims 2 to 4,
The image file generation method, wherein the image correction in the target image correction process includes tone curve correction and memory color correction. The image file generation method according to claim 5,
The plurality of image correction parameters are the same as the image correction parameters used for the specific image correction, and the selection order of the target correction parameters in the target correction parameter selection process is the same for each image correction parameter in the specific image correction. The image file generation method is the same as the correction execution order. The image file generation method according to claim 6,
The image file generation method, wherein the selection order is an order of a highlight correction parameter, a brightness correction parameter, a contrast correction parameter, a color balance correction parameter, and a memory color correction parameter. An image file generation method according to any one of claims 4 to 7,
The step (a) is a step of generating the image correction parameter set for each combination of the specific image generation device and an output device used for outputting image data generated by the specific image generation device. Image file generation method. An image file generation method according to any one of claims 4 to 7,
In the step (a), the image correction parameter set is generated for each combination of the specific image generation device, an output device used to output image data generated by the specific image generation device, and a print medium. An image file generation method as a process. An image file generation method according to any one of claims 2 to 9,
The step (a) is an image file generation method in which the image correction parameter set is generated for a plurality of shooting scene modes that can be used by the specific image generation apparatus. An image correction parameter transmission system that transmits an image correction parameter set for a specific image generation device in the form of an installer file via a network,
A device information acquisition unit that acquires user device information that is a combination of an image generation device and an image output device used by a user via the network;
An installer file transmitting unit that transmits an installer file including at least one image correction parameter set suitable for the combination and an installation program for the image correction parameter set to the user based on the user device information;
With
An image correction parameter transmission system, wherein the installer file has a function of storing the image correction parameter set in a memory in an image generation apparatus used by the user by an execution operation of the installation program. An image correction parameter transmission method for transmitting an image correction parameter set for a specific image generation device in the form of an installer file via a network,
(A) acquiring user device information that is a combination of an image generation device and an image output device used by a user via the network;
(B) transmitting to the user an installer file including at least one image correction parameter set suitable for the combination and an installation program for the image correction parameter set based on the user device information;
With
An image correction parameter transmission method, wherein the installer file has a function of storing the image correction parameter set in a memory in an image generation apparatus used by the user by an execution operation of the installation program.

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