JP5322326B2 - Color correction table calculation circuit, color correction device, display device, color correction method, and program - Google Patents

Description

The present invention relates to a color correction table calculation circuit, a color correction device , a display device , a color correction method , and a program .

  In general, an image printed by a printing device has a different color when compared to an image displayed on a display device such as a liquid crystal monitor using the same image data. In order to correct this color difference, calibration is performed by comparing the display device with the actually printed matter. However, in order to calibrate the color of a printed material, it is necessary to create a printed material for proofing by printing a large number of copies in order to create a master or obtain mechanical stability of the printing press. For this reason, calibrating the color with a test-printed printed material is a burden on the creator of the printed material in terms of time and cost, and a large amount of paper is consumed for proofing the color, which wastes resources. It is also.

  Therefore, in graphic design and printing industries where the final product is a printed material and accurate color reproduction is required, there is a strong demand for a print preview function that allows the user to check the color of the printed material on a display device such as a liquid crystal display during content creation. It was done. In response to this requirement, color management technology that maintains a constant color tone between work processes between content creation and printing is being used and is becoming popular.

For example, some dedicated application products on the market such as Adobe's PHOTOSHOP (registered trademark) provide a high-precision print preview function based on a profile. The profile is data describing input / output characteristics of an image, a display device, and a printing device.
However, the dedicated application product as described above places a heavy burden on the user, such as a limited image format corresponding to color management including print preview, and the need to switch from an application familiar to the user. That is, the dedicated application product as described above has a problem that it is difficult to provide a print preview function for various applications and image formats used in content creation and display.

  In particular, in the case of dynamic preview in which the display content changes depending on the operation of the user who browses the content and the elapsed time, and a print preview of a web page that does not fit on one screen of the display device, the work efficiency is significantly reduced. This involves capturing the screen for each changed display content, converting the captured image into an image format that can be input to the dedicated application product, inputting it, and performing a print preview for each screen to check it. Because.

To solve the above problem, a print preview function that does not use a dedicated application product has been proposed (Patent Document 1).
In addition, a technique for performing color conversion to obtain color characteristics displayed on the target device in the device used, that is, a technique of a color conversion engine used for preview has been proposed (Patent Document 2).

JP 2007-251237 A JP 2008-085980 A

However, in the technique proposed in Patent Document 1, using an optical measurement device that is not originally related to content creation, a display device to be used and a printed matter in which a reference image is printed for each setting of the printing device. Careful measurement is required. For the user, there is a problem that the purchase and maintenance of the optical measurement device and the printing and measurement of the reference image are burdensome.
In general, a design company selectively uses a plurality of printing stations according to printed matter. At this time, the design contractor checks the color while updating the rendering intent to be passed to the printing shop as needed, so it is not realistic in terms of work efficiency to obtain measured characteristics for each printing device of each of the plurality of printing shops. There is a problem. Here, the rendering intent is a color conversion parameter.

  Furthermore, the above-described dedicated application product realizes a print preview function by combining a profile of an image, a printing device and a display device, and a color conversion engine. Therefore, it is difficult to synchronize with the characteristics of the profile and the color conversion engine in the dedicated application product with the correction circuit that only acquires the actual measurement characteristics of the display device and the printing device according to the technique proposed in Patent Document 1, It is difficult to express similar colors.

Examples of the color conversion engine include various products such as Adobe ACE, Microsoft ICM 2.0, WCS, and Apple ColorSync (registered trademark). Each of these color conversion engines has unique conversion parameters and display characteristics, and the profiles of these color conversion engines are represented by a large number of parameters ranging from several tens of items. It is very difficult to reproduce characteristics similar to those of the color conversion engine using other software.
For this reason, even if the print preview function is configured by using the technique of Patent Document 1, the print preview function with a color different from that of a commonly used dedicated application product is not sufficient for commercial use. There is a problem that there is.

  The technology described in Patent Document 2 is a technology that constitutes a color conversion engine, and does not realize a color similar to that of an existing dedicated application product, that is, a color that is widely used by color management. However, it has the same problem as Patent Document 1.

The present invention has been made in view of the above-described problems, and a color correction table calculation circuit, a color correction device , and a display that can reproduce colors by color management that is generally used regardless of the image format to be displayed. An object is to provide an apparatus , a color correction method , and a program .

The color correction device of the present invention is a color correction device that corrects an input image signal and outputs the color signal to a display device. The color correction device includes a reference image output unit, a reference image decomposition unit, and a lookup A table setting unit; and an image conversion unit, wherein the reference image output unit generates a reference image including a color chart that is information indicating a color, and transmits the reference image to a color conversion device and the reference image decomposition unit. The color conversion device performs color conversion on the reference image based on parameters indicating color characteristics relating to the reference image, the printing device , and the display device , and converts the reference image obtained by the color conversion into the reference image decomposition. The reference image decomposition unit associates the color chart before and after performing the color conversion and outputs the color chart to the lookup table setting unit, and the lookup table setting unit performs the color conversion. Previous group It said color chips included in the image, from the correspondence between the color chips included in the color conversion has been the reference image, to generate the color correction information used for color correction, outputs the color correction information to the image conversion unit and, wherein the image conversion section performs color correction on the image signal based on the color correction information, and outputs the image signal color correction on the display device.
The color correction table calculation circuit of the present invention is a color correction table calculation circuit that generates color correction information used when color correcting an image signal, and the color correction table calculation circuit includes a reference image output unit, A reference image decomposition unit; and a lookup table setting unit. The reference image output unit generates a reference image including a color chart that is information indicating a color, and outputs the reference image to the color conversion device and the reference image decomposition unit. The reference image is output, and the color conversion device color-converts the reference image based on parameters indicating color characteristics relating to the reference image, the printing device , and the display device, and the color-converted reference image Transmitted to the reference image decomposition unit, the reference image decomposition unit associates the color charts before and after performing the color conversion, outputs the color charts to the lookup table setting unit, and sets the lookup table Parts are said color chips included in the reference image before performing the color conversion, from the correspondence between the color chips included in the color conversion has been the reference image to generate a color correction information used for color correction It is characterized by that.
The display device of the present invention is a display device that corrects and displays an input image signal, and the display device includes a reference image output unit, a reference image decomposition unit, a lookup table setting unit, An image conversion unit; and a display unit. The reference image output unit generates a reference image including a color chart that is information indicating a color, and transmits the reference image to a color conversion device and the reference image decomposition unit. Output the color conversion device, color-converting the reference image based on a parameter indicating color characteristics relating to the reference image, the printing device , and the display device , and the reference image decomposition The reference image decomposition unit associates the color chart before and after performing the color conversion and outputs the color chart to the lookup table setting unit, and the lookup table setting unit performs the color conversion. Previous said Said color chips included in the semi-images, the correspondence between the color chips included in the color conversion has been the reference image, to generate the color correction information used for color correction, the the color correction information to the image conversion unit outputting, the image converter may have line color correction on the image signal based on the color correction information, and outputs the image signal color correction on the display unit, the display unit, the color correction It characterized the Turkey to display the image signal.
The color correction method of the present invention is a color correction method in a color correction device that corrects an input image signal and outputs it to a display device, and generates a reference image including a color chart that is information indicating the color. A process in which the color conversion device receives the reference image color-converted based on a parameter indicating color characteristics relating to the reference image, the printing device, and the display device, and the color before and after performing the color conversion. a step of associating the votes, and the color chips included in the reference image before performing the color conversion, from the correspondence between the color chips included in the color conversion has been the standard image, the color correction information used for color correction and generating a performs color correction on the image signal based on the color correction information, characterized in that the image signals obtained by the color correction comprises the step of outputting to the display device.
The color correction method of the present invention is a color correction method for generating color correction information used when color correcting an image signal, and a process of generating a reference image including a color chart that is information indicating a color; A process in which the color conversion device receives the reference image color-converted based on a parameter indicating color characteristics relating to the reference image, the printing device, and the display device; and a step of associating the color chart before and after performing the color conversion A process of generating color correction information used for color correction from the correspondence between the color chart included in the reference image before color conversion and the color chart included in the color-converted reference image It is characterized by comprising.
Further, the program of the present invention includes a process of generating a reference image including a color chart that is information indicating color in a computer that generates color correction information to be used when color correcting an image signal, and a color conversion device includes the reference A process of receiving the reference image color-converted based on a parameter indicating color characteristics relating to an image, a printing apparatus, and the display apparatus, a process of associating the color chart before and after the color conversion, and the color conversion A program for executing a process of generating color correction information used for color correction from the correspondence between the color chart included in the previous reference image and the color chart included in the color-converted reference image It is.

  According to the present invention, it is possible to generate a color conversion table for reproducing the color tone of the target output device on the display device without using an optical measuring instrument, and to display an image to be displayed using the generated color correction information. By correcting the tint, it is possible to reproduce the tint by commonly used color management regardless of the image format.

1 is a schematic block diagram illustrating a configuration example of a color correction table calculation circuit 11 and a color correction apparatus 1 using the color correction table calculation circuit 11 according to an embodiment of the present invention. It is the figure which showed an example of the reference | standard image in the same embodiment. It is a figure which shows an example of the reference | standard image by which color conversion in the same embodiment was carried out. 4 is a flowchart illustrating the operations of the color correction apparatus 1 and the color conversion apparatus 2 according to the embodiment.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic block diagram illustrating a configuration example of a color correction table calculation circuit 11 and a color correction apparatus 1 using the color correction table calculation circuit 11 according to an embodiment of the present invention.
The color correction apparatus 1 according to the present embodiment is an apparatus that performs color correction based on the color characteristics output by the output device, the color characteristics output by the display device 4, and the like when performing print preview. The print preview is an operation for confirming in advance the color of the printed matter output by the printing device (output device).

  In FIG. 1, the color correction device 1 transmits a reference image and parameters used for color conversion to the color conversion device 2, receives the converted reference image from the color conversion device 2, and uses the reference image before and after conversion. Color correction information is calculated. The color correction device 1 performs color correction based on the color correction information obtained by calculating the image signal input from the video output device 3 such as a personal computer or a video device, and displays the color-corrected image signal on the display device 4. Send to. Here, the display device 4 is an LCD (liquid crystal display), a PJ (projector), or the like, and performs video display based on an image signal subjected to color correction.

  Parameters used for color conversion include rendering intent information, image profile information corresponding to the reference image, print profile information (output profile information) corresponding to the printing apparatus, and display profile information corresponding to the display apparatus 4. And are included. There are various standards for image profile information such as sRGB, AdobeRGB, NTSC, and DCI. There are various standards for print profile information such as JapanColor, SWOP, and EuroPress. The display profile information is information indicating the characteristics of the display device 4 used for the preview, and is different for each individual display device 4. The rendering intent information is information indicating a color space conversion method, and is specifically information indicating conditions for color replacement and color cut-out performed at the time of color conversion. The profile information is data describing the image, the input / output characteristics of the display device 4 and the printing device. Here, a case will be described in which a printed material for printing an image of the sRGB standard in accordance with the JapanColor standard is previewed.

  Here, the color conversion apparatus 2 performs color conversion on the received reference image based on parameters, and includes color conversion engines 21 and 22 as shown in the figure. The color conversion device 2 performs color conversion of the received reference image from the sRGB standard to the JapanColor standard by the two color conversion engines 21 and 22 provided, and further performs color conversion from the JapanColor standard to the color space of the display device 4, The reference image that has undergone color conversion is transmitted to the color correction apparatus 1. The color conversion engines 21 and 22 are, for example, software commonly used by applications such as Adobe's ACE, Microsoft's ICM2.0 or WCS, and Apple's ColorSync (registered trademark), or an OS. It is.

The color correction apparatus 1 includes a color correction table calculation circuit 11 and an image conversion circuit 12.
The color correction table calculation circuit 11 includes a reference image output unit 111, a profile setting unit 112, a display profile setting unit 113, a reference image decomposition unit 114, and a 3DLUT (3 Dimension Look Up Table) setting. Unit 115 (lookup table setting unit).

  The reference image output unit 111 generates the reference image pattern shown in FIG. 2 and outputs the pattern to the color conversion device 2 and the reference image decomposition unit 114. The reference image includes a total of 9 × 9 × 9 correction point colors obtained by combining nine points obtained by extracting 256 gradations (8 bits) of RGB (red, green, and blue) every 32 gradations. . FIG. 2 is a diagram showing an example of a reference image in the embodiment. As shown in the drawing, the reference image is an image in which color charts of 9 × 9 × 9 correction points are arranged, and the color of (R, G, B) = (255, 255, 255) in the area A Is arranged, the color of (R, G, B) = (255, 255, 224) is arranged in the region B, and the color of (R, G, B) = (255, 224, 224) is arranged in the region C In the region D, the colors (R, G, B) = (224, 224, 224) are arranged. The color chart is information indicating colors and includes values indicating the levels (R, G, B) of the three colors of red, green, and blue.

The profile setting unit 112 receives image profile information selected by the user, print profile information, and rendering intent information, and inputs the input image profile information, print profile information, and rendering intent information. Output to the color conversion device 2.
The display profile setting unit 113 stores in advance the R / G / B points xy chromaticity of the display device 4 and gamma characteristics indicating the luminance gradation characteristics of the display device 4. The display profile setting unit 113 receives white point information indicating the luminance and color temperature of the white point selected by the user, and stores the white point information and the stored R / G / B point xy chromaticity. And the gamma characteristic are combined to generate display profile information for setting the brightness and color temperature of the white point of the display device 4 and output it to the color conversion device 2 and the display device 4. In the display device 4, the brightness and color temperature of the white point are set to the brightness and color temperature selected by the user based on the display profile information.

The reference image decomposition unit 114 receives the color-converted reference image (FIG. 3) from the color conversion device 2 and receives the reference image (FIG. 2) from the reference image output unit 111. The reference image decomposition unit 114 divides the color charts included in the reference images before and after color conversion into 9 × 9 × 9 color charts, and before and after color conversion is performed on each of the divided color charts. And output to the 3DLUT setting unit 115 in association with each other.
FIG. 3 is a diagram showing an example of a color-converted reference image in the same embodiment. In the reference image that has been color-converted, 9 × 9 × 9 color charts that have been color-converted are arranged in the same manner as the reference image (FIG. 2). As shown in the drawing, the color of (R, G, B) = (255, 255, 255) is arranged in the region A ′, and (R, G, B) = (255, 243, 211) is arranged in the region B ′. The color is arranged, the color of (R, G, B) = (200, 210, 223) is arranged in the region C ′, and the color of (R, G, B) = (230, 225, 200) is arranged in the region D. Is arranged. 2 corresponds to the area A ′ of FIG. 3 that has been color-converted by the color conversion device 2. Similarly, the color of the region B corresponds to the color of the region B ′, the color of the region C corresponds to the region C ′, and the color of the region D corresponds to the color of the region D ′.

  The 3DLUT setting unit 115 generates color correction information used for color correction from the color chart associated by the reference image decomposition unit 114. Here, the color correction information includes information for color correction for each of 9 × 9 × 9 color charts. For example, when the color chart (R, G, B) = (255, 255, 224) of the area B in FIG. 2 is input, the color chart (R, G, B) = (255) of the area B ′ in FIG. , 243, 211) are included.

  The image conversion circuit 12 includes a 3DLUT (three-dimensional lookup table) 121. The 3DLUT 121 is configured by a table that outputs color-corrected R, G, and B color information at a time when R, G, and B color information is input for each pixel. The 3DLUT 121 stores color correction information of 9 × 9 × 9 color charts that are correction points input from the 3DLUT setting unit 115. The 3DLUT 121 performs color correction on the color of each pixel included in the image signal input from the video output device 3 in accordance with the color correction information, and outputs the color-corrected image signal to the display device 4.

  The image signal input from the video output device 3 to the 3DLUT 121 is a signal of 256 gradations (8 bits) for each of RGB. Therefore, the 3DLUT 121 performs color correction by approximating the color of each pixel of the image signal as the color of the closest correction point with respect to the signal corresponding to each correction point. Note that the 3DLUT 121 calculates a correction value by linear interpolation, Lagrange interpolation, or the like based on the correction point information instead of the approximation to the correction point described above, and performs color correction on the color of each pixel of the image signal. You may go.

  Next, the operation of the color correction apparatus 1 will be described with reference to FIG. FIG. 4 is a flowchart showing operations of the color correction apparatus 1 and the color conversion apparatus 2 in the same embodiment. In addition, a case where “perceptual matching” is selected as the rendering intent, 5000 K is selected as the color temperature of the illumination that illuminates the printed matter, and input to the color correction apparatus 1 will be described.

The profile setting unit 112 receives an sRGB standard ICC profile that is image profile information, a JapanColor standard ICC profile that is a print profile, and rendering intent information that indicates “perceptual matching” selected by the user. Is done. The display profile setting unit 113 receives information indicating 5000K, which is white point information selected by the user (step St101).
The sRGB standard profile and the JapanColor standard profile described above are attached to commercially available application software and are disclosed free of charge via the Internet, so that the user can easily use them.

The display profile setting unit 113 generates display profile information in which R / G / B point xy chromaticity and gamma characteristics stored in advance and information indicating 5000K input are combined, and the generated display profile information Is output to the color conversion device 2 and the display device 4 (step St102).
The reference image output unit 111 generates a reference image (FIG. 2) in which 9 × 9 × 9 color charts indicating correction points in the 3DLUT 121 are combined (step St103).
The reference image output unit 111 transmits the generated reference image to the color conversion device 2. The profile setting unit 112 transmits the input image profile information, print profile information, and rendering intent information to the color conversion device 2. The display profile setting unit 113 transmits the generated display profile information to the color conversion device 2 (step St104).

In the color conversion device 2, the color conversion engine 21 converts the input reference image from the sRGB standard to the JapanColor standard based on the rendering intent information using the image profile information as an input profile and the print profile information as an output profile ( Step St111).
Subsequently, the color conversion engine 22 converts the reference image converted to the JapanColor standard into the color space of the display device 4 based on the rendering intent information using the print profile information as an input profile and the display profile information as an output profile. (Step St112). As a result, the color-converted reference image (FIG. 3) reflects the JapanColor standard corresponding to the color characteristics output from the printing apparatus, and the image (FIG. 3) corresponding to the color characteristics of the display device 4 has a color. Converted.

In the color correction device 1, the reference image decomposition unit 114 receives the color-converted reference image from the color conversion engine 22 (Step St105).
The reference image decomposition unit 114 divides the color charts included in the color-converted reference image and the reference image input from the reference image output unit 111, and associates the color charts before and after the color conversion to set the 3DLUT. Output to the unit 115. The 3DLUT setting unit 115 generates color correction information used for color correction from the input color chart (step St106). The 3DLUT setting unit 115 stores the generated color correction information in the 3DLUT 121 (step St107).
The 3DLUT 121 performs color correction on the image signal input from the video output device 3 according to the stored color correction information and outputs the image signal to the display device 4 (step S108).

By performing the above processing, the print unit preview of the printed matter output from the printing device is performed on the display device 4.
As described above, by using the color correction apparatus 1, it is possible to perform a print preview for confirming the color of a printed matter without using an application for creating content, and thus the application is not limited to an application, an image format, or the like. Print preview can be performed. For users, print preview can be performed using a familiar application, so it is not necessary to convert the image format that was used for print preview, so work efficiency can be improved. .
In addition, since the color correction is performed on the image signal output from the video output device 3 by using the color correction device 1, a print preview of dynamic content in which the display content changes depending on the operation of the viewer or the passage of time can be easily performed. Can be done.

In addition, when performing a print preview, there is no need to measure the color characteristics of the printing apparatus and the display apparatus 4, and various profile information, white point information, and rendering intent, which are parameters related to the print preview, are changed. In this case, since the color of the printed material can be easily reproduced, the burden on the user can be reduced. In addition, since it is not necessary to measure the color characteristics of the printing device and the display device 4, the user does not need to purchase an optical measuring device, and the burden on the user is reduced.
Further, since a color conversion engine of a dedicated application product that is generally used is used as the color conversion device 2, the same color tone as that of the dedicated application product can be reproduced, which is convenient for commercial users. high.

  Further, since the color correction apparatus 1 performs color correction similar to that of the dedicated application product on the image signal output from the video output apparatus 3, a print preview function for a workflow generally used in the printing industry or the like. Can be provided and can be easily introduced into a workflow that has already been used. In addition, since the same print preview function can be provided for different workflows, differences in print preview between workflows can be eliminated, and workflow integration can be facilitated.

  In the above-described embodiment, the reference image output unit 111 is configured to output a reference image in which 256 gradations of RGB are extracted every 32 gradations. The correction point may be changed according to the image signal to be output. For example, any one of color evaluation patterns such as ISO12646, GRACoL206, and FOGRA39 may be selected by the user, and the reference image may be generated based on the selected color evaluation pattern. As a result, the conversion error in the color conversion device 2 can be reflected in the correction point by the image characteristics corresponding to the pattern of the image signal, the purpose of use, etc., and the error in the color conversion can be suppressed. The image characteristics include, for example, that there are many dark parts with black as the center in an image signal based on a movie film.

In addition, a reference image may be generated by placing importance on colors with high human visibility such as skin color, that is, by arranging a large number of correction points in a color close to skin color. Thereby, it is possible to improve the reproducibility of the print preview for a printed matter such as a photograph of a person.
Further, the reference image output unit 111 includes a reference image including 9 × 9 × 9 correction point colors in total, which is a combination of 9 points obtained by extracting 256 gradations (8 bits) of RGB every 32 gradations, A reference image with only gray that changes from black to white as a correction point is generated, and a reference image is displayed by the user when performing a print preview of a black-and-white print including gray and when performing a print preview of a color print. May be selected. Thereby, a print preview according to the printed matter can be performed, and reproducibility can be improved.

    Further, in the above-described embodiment, the color conversion apparatus 2 performs the reference image from the RGB value of the sRGB standard to the CMYK value of the JapanColor standard, and from the CMYK value of the JapanColor standard to the RGB value of the color space of the display apparatus 4 by performing color conversion twice. However, the present invention is not limited to this, and color information dependent on input / output devices such as RGB and CMYK is converted to PCS information in a color space independent of the input / output devices, and the PCS information depends on the input / output devices. It may be converted into color information. Here, the PCS standard indicates a profile combined color space, and indicates a color space independent of input / output devices such as display devices such as Lab and XYZ, and printing devices.

  In this case, the color conversion device 2 is provided with three color conversion engines. Then, the first color conversion engine converts the reference image input based on the rendering intent information from the sRGB standard to the PCS standard using the sRGB standard as image profile information as an input profile. Next, the second color conversion engine corrects the PCS standard value of the reference image converted into the PCS standard based on the JapanColor standard and the rendering intent information which are the print profile information. As a result, the reference image converted to the PCS standard is an image reflecting the print profile characteristics. Further, the third image conversion engine uses the display profile information as output profile information, and converts the reference image converted by the second color conversion engine based on the rendering intent information from the PCS standard to the RGB value of the color space of the display device. The converted reference image is output to the reference image decomposition unit 114.

In the above-described embodiment, the reference image including 9 × 9 × 9 color charts as correction points has been described. However, the present invention is not limited to this, and the number of correction points depends on the storage capacity of the 3DLUT 121. May be changed.
In the above-described embodiment, the case where the color of the printed matter output by the printing device is reproduced on the display device 4 has been described. However, the present invention is not limited to this, and the color of the output device that outputs an image other than the printing device is used. You may make it reproduce on the display apparatus 4. FIG. You may make it reproduce on the display apparatus 4 (LCD display) the color of the image shown by the display apparatus different from the display apparatus 4, for example, a projector. In this case, profile information corresponding to the output device is used instead of the print profile information.

In the above-described embodiment, the display profile setting unit 113 is configured to input white point information. However, the display profile setting unit 113 may generate display profile information based on the white point information included in the image profile information. .
In the above-described embodiment, the display profile setting unit 113 may use a standard value such as “2.2” as the gamma characteristic stored in advance. In this case, the display profile information generated by the display profile setting unit 113 includes a standard gamma characteristic represented by a standard value or a gamma correction value for adjusting the display device 4 to the standard gamma characteristic.

  In the above-described embodiment, the color conversion necessary for the print preview is separated into two stages, namely, gray scale adjustment for correcting the white point and gradation characteristics, and color adjustment for correcting the color gamut, and the 3DLUT 121 Although only color adjustment is performed to achieve high image quality, grayscale adjustment may also be performed by the 3DLUT 121. In this case, the 3DLUT 121 changes the stored color correction information based on the brightness and color temperature of the white point of the display profile information output from the display profile setting unit 113, and performs color processing on the input image signal. In addition to correction, the brightness and color temperature of the white point are corrected. At this time, since the display device 4 does not need to receive display profile information from the display profile setting unit 113, a generally used display or the like can be used, and versatility can be improved.

The display profile information transmitted from the display profile setting unit 113 to the display device 4 may include a black level correction value or a target value. In that case, the display profile setting unit 113 inputs black level information indicating the luminance of black and white, which is input from the outside by a user or the like, or information indicating the luminance of black and white of a printed material included in the printing profile information. Based on the display profile information, a correction value for correcting the black level of the display device 4 or a target value of the black level is calculated. The display profile setting unit 113 corrects the black level by transmitting a correction value or a target value for the black level of the display device 4 to the display device 4 to thereby correct the black floating or darkening of the image displayed on the display device 4. It is possible to improve the matching with the actual printed matter by suppressing the accuracy of the print preview. As information indicating the luminance of black and white included in the black level information, for example, each candela value [cd], a ratio of luminance values of white and black, and the like are included.
Further, the color correction information stored in the 3DLUT 121 may be changed to perform color correction on the image signal to which the 3DLUT 121 is input and to correct the black level.

  The 3DLUT 121 may calculate additional correction values based on color vision abnormalities and different color vision characteristics such as the CIE 1964X10Y10Z10 color system, and may perform color correction on the color of each pixel of the input image signal.

DESCRIPTION OF SYMBOLS 1 Color correction apparatus 2 Color conversion apparatus 3 Video | video output apparatus 4 Display apparatus 11 Color correction table calculation circuit 12 Image conversion circuit 21, 22 Color conversion engine 111 Reference | standard image output part 112 Profile setting part 113 Display profile setting part 114 Reference | standard image decomposition part 115 3DLUT Setting Unit 121 3DLUT

Claims (10)

A color correction device that corrects the color of an input image signal and outputs it to a display device,
The color correction apparatus includes a reference image output unit, a reference image decomposition unit, a lookup table setting unit, and an image conversion unit,
The reference image output unit generates a reference image including a color chart that is information indicating a color, and outputs the reference image to a color conversion device and the reference image decomposition unit.
The color conversion device color-converts the reference image based on a parameter indicating color characteristics relating to the reference image, the printing device , and the display device , and transmits the color-converted reference image to the reference image decomposition unit. ,
The reference image decomposition unit associates the color chart before and after performing the color conversion, and outputs the color chart to the lookup table setting unit,
The look-up table setting unit determines the color used for color correction based on the correspondence between the color chart included in the reference image before the color conversion and the color chart included in the color-converted reference image. Generating correction information, and outputting the color correction information to the image conversion unit;
The image converting unit performs color correction on the image signal based on the color correction information, a color correction apparatus of the image signal obtained by color correction and outputs to the display device. The parameter is
Image profile information indicating color characteristics corresponding to the reference image, print profile information indicating color characteristics corresponding to the printing apparatus, display profile information indicating color characteristics corresponding to the display apparatus, and a color space in color conversion The color correction apparatus according to claim 1, further comprising: a rendering intent indicating a conversion method. The color correction apparatus according to claim 1, wherein the reference image generated by the reference image output unit includes a plurality of reference images, and the reference image selected according to the image signal is generated. . Either of the white point information indicating the luminance or color temperature of the input white point and the display characteristic value stored in advance in the display device, information for setting the luminance or color temperature of the white point, and gamma characteristic information The display profile setting part which produces | generates the display profile information containing either one or both, and outputs this display profile information to the said display apparatus is provided. The one of the Claims 1-3 characterized by the above-mentioned. Color correction device. The display profile setting unit calculates black level correction information for correcting the black level of the display device based on black level information indicating the input black level or the output profile information,
The color correction apparatus according to claim 4, wherein the display profile information includes the black level correction information calculated by the display profile setting unit. A color correction table calculation circuit for generating color correction information used for color correction of an image signal,
The color correction table calculation circuit includes a reference image output unit, a reference image decomposition unit, and a lookup table setting unit.
The reference image output unit generates a reference image including a color chart that is information indicating a color, and outputs the reference image to a color conversion device and the reference image decomposition unit.
The color conversion device performs color conversion on the reference image based on a parameter indicating color characteristics relating to the reference image, the printing device , and the display device , and transmits the color-converted reference image to the reference image decomposition unit. And
The reference image decomposition unit associates the color chart before and after performing the color conversion, and outputs the color chart to the lookup table setting unit,
The look-up table setting unit determines the color used for color correction based on the correspondence between the color chart included in the reference image before the color conversion and the color chart included in the color-converted reference image. color correction table calculating circuit and generates the correction information. A display device for color-correcting and displaying an input image signal,
The display device includes a reference image output unit, a reference image decomposition unit, a lookup table setting unit, an image conversion unit, and a display unit.
The reference image output unit generates a reference image including a color chart that is information indicating a color, and outputs the reference image to a color conversion device and the reference image decomposition unit.
The color conversion device performs color conversion on the reference image based on a parameter indicating color characteristics relating to the reference image, the printing device , and the display device , and transmits the color-converted reference image to the reference image decomposition unit. And
The reference image decomposition unit associates the color chart before and after performing the color conversion, and outputs the color chart to the lookup table setting unit,
The look-up table setting unit determines the color used for color correction based on the correspondence between the color chart included in the reference image before the color conversion and the color chart included in the color-converted reference image. Generating correction information, and outputting the color correction information to the image conversion unit;
The image converter may have line color correction on the image signal based on the color correction information, and outputs the image signal color correction on the display unit,
Wherein the display unit, that displays the color corrected the image signal
Display device comprising a call. A color correction method in a color correction device that corrects the color of an input image signal and outputs it to a display device,
A process of generating a reference image including a color chart which is information indicating color;
A process in which the color conversion device receives the reference image that has been color-converted based on a parameter indicating color characteristics relating to the reference image, the printing device, and the display device;
A step of associating the color chart before and after performing the color conversion,
A step of generating color correction information used for color correction from the correspondence between the color chart included in the reference image before the color conversion and the color chart included in the color-converted reference image;
Color correction method characterized by comprising the step of outputting performs color correction on the image signal based on the color correction information, the image signal color correction on the display device. A color correction method for generating color correction information for use in color correction of an image signal,
A process of generating a reference image including a color chart which is information indicating color;
A process in which the color conversion device receives the reference image color-converted based on a parameter indicating color characteristics relating to the reference image, the printing device, and the display device;
Associating the color chart before and after the color conversion;
A step of generating color correction information used for color correction from correspondence between the color chart included in the reference image before the color conversion and the color chart included in the color-converted reference image;
A color correction method comprising: A computer that generates color correction information for use in color correction of image signals
A process of generating a reference image including a color chart which is information indicating color;
A process in which the color conversion device receives the reference image color-converted based on a parameter indicating color characteristics relating to the reference image, the printing device, and the display device;
Associating the color chart before and after the color conversion;
A step of generating color correction information used for color correction from correspondence between the color chart included in the reference image before the color conversion and the color chart included in the color-converted reference image;
A program for running

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