JP6237141B2 - Gradation correction apparatus and program - Google Patents

Description

  The present invention relates to a gradation correction apparatus and a program.

  As a prior art described in the publication, a display unit that displays a color chart based on a color chart, a digital camera that generates color chart image data by imaging the color chart displayed on the display unit, and a digital camera Display characteristics of the display means based on the color chart image data, the original color chart data used for display on the display means, color information given in advance to the color chart, and imaging characteristic data of the digital camera Correction data calculating means for calculating correction data for correcting the display characteristics to reproduce the original color of the image, and correcting the image data supplied to the display means using the correction data calculated by the correction data calculating means There is an image color expression system including a correction unit (see Patent Document 1).

JP 2004-32399 A

  An object of the present invention is to bring a gradation characteristic of a display device close to a target gradation characteristic based on a result of photographing by the photographing apparatus without using a characteristic unique to the photographing apparatus.

According to the first aspect of the present invention, there is provided test image data generating means for generating test image data for displaying a test image including a plurality of images having different input gradation values on a display screen of a display device, and the test image data a plurality of outputs the previous SL test image displayed on the display screen acquires imaging data obtained by photographing by the photographing device, corresponding to each of a plurality of images of those the test image that put on the image pickup data on the basis of A gradation characteristic creating means for creating a relative gradation characteristic of the display device based on the gradation value, and a level for correcting the input / output characteristic of the display device based on the relative gradation characteristic. tone correction data viewing including the gradation correction data generation means for generating said test image data creating means is constituted by color components of R (red), G (green) and B (blue), each input floor Multiple images with different key values The test image data for displaying the test image is created, and the gradation characteristic creating means obtains the imaging data, creates the relative gradation characteristic for each color of RGB, and The tone correction data creation means is a tone correction device that creates tone correction data for each color of RGB .
According to a second aspect of the present invention, the test image data creating means includes the lowest gradation image having the lowest input gradation value, the highest gradation image having the highest input gradation value, and the input gradation value The test image data including the lowest gradation image and the intermediate gradation image between the highest gradation image as the test image is created, and the gradation characteristic creating means includes the lowest floor in the imaging data. The relative tone characteristics are created by normalizing the output tone value of the intermediate tone image using the output tone value of the tone image and the output tone value of the highest tone image. The gradation correction apparatus according to claim 1, wherein:
The invention described in claim 3 further includes storage means for storing a target gradation characteristic in the display device, and the gradation correction data creating means reads out the relative gradation characteristic and the storage means. The gradation correction apparatus according to claim 1, wherein the gradation correction data is created based on the target gradation characteristic.
The invention according to claim 4 is based on the function of creating test image data for causing a computer to display a test image including a plurality of images having different input gradation values on a display screen of the display device, and the test image data. the display front Symbol test image displayed on the screen to acquire a captured data obtained by photographing by the photographing apparatus, a plurality of output floor corresponding to each of the plurality of images before Symbol test images that put on the image pickup data Te A function for creating a relative gradation characteristic of the display device based on a tone value, and a gradation correction data for correcting an input / output characteristic of the display device based on the relative gradation characteristic The function of creating the test image data is configured by R (red), G (green), and B (blue) color components, and a plurality of images having different input tone values. Display the test image including The function for creating the test image data and creating the gradation characteristics is to acquire the imaging data, create the relative gradation characteristics for each color of RGB, and obtain the gradation correction data. The function to be created is a program that creates gradation correction data for each color of RGB .

According to the first aspect of the present invention, the gradation characteristic of the display device can be adjusted based on the result of photographing by the photographing device, without using the characteristic unique to the photographing device, as compared with the case where this configuration is not provided. The target gradation characteristics can be brought close to. According to the first aspect of the present invention, the color of the color image displayed on the display device can be made closer to the target color as compared with the case where the present configuration is not provided.
According to the second aspect of the present invention, the gradation characteristics of the display device can be made closer to the target gradation characteristics as compared with the case where the present configuration is not provided.
According to the third aspect of the present invention, the gradation characteristics of the display device can be made closer to the target gradation characteristics as compared with the case where the present configuration is not provided.
According to the fourth aspect of the present invention, the gradation characteristic of the display device can be adjusted based on the result of photographing by the photographing device, without using the characteristic unique to the photographing device, as compared with the case without this configuration. The target gradation characteristics can be brought close to.

It is the figure which showed an example of the structure of the image display system to which embodiment of this invention is applied. It is the figure which showed the hardware constitutions of the computer apparatus. It is a flowchart for demonstrating the procedure of a gradation correction operation | movement. It is a figure which shows an example of a structure of the 1st test image used by gradation correction | amendment operation | movement. (A), (b) is a figure for demonstrating the relationship between the display area of the 1st test image in a display screen, and the imaging area by a digital camera. (A)-(d) is a figure for demonstrating the gradation correction | amendment of red (R) based on 1st imaging data. It is a figure which shows an example of a structure of the 2nd test image used by gradation correction | amendment operation | movement. (A)-(d) is a figure for demonstrating the gradation correction | amendment of red (R) based on 1st imaging data and 2nd imaging data.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
FIG. 1 is a diagram illustrating an example of a configuration of an image display system 10 to which the exemplary embodiment of the present invention is applied.
The image display system 10 includes a computer device 20 that creates image data for display, a display device 30 that displays an image based on the image data created by the computer device 20 on a display screen 31, and the computer device 20. And an input device 40 for receiving an input or the like.

  In the image display system 10, the computer device 20 and the display device 30 are connected via, for example, a DVI (Digital Visual Interface), and the computer device 20 and the input device 40 are connected via, for example, a USB (Universal Serial Bus). ing. The computer device 20 and the display device 30 may be connected via HDMI (High-Definition Multimedia Interface: registered trademark), DisplayPort, or D-sub instead of DVI.

  The computer device 20 is a so-called general-purpose personal computer. In the computer device 20, image data is created by operating various application software under the management of an OS (Operating System).

  Further, the display device 30 is configured by a device having a function of displaying an image by additive color mixing, such as a liquid crystal display for a PC, a liquid crystal television, or a projector. Therefore, the display method in the display device 30 is not limited to the liquid crystal method. Here, in the present embodiment, it is assumed that the display device 30 displays an image using three colors of red (R), green (G), and blue (B). In FIG. 1, the display screen 31 is provided in the display device 30. However, when a projector is used as the display device 30, for example, the display screen 31 is a screen or the like provided outside the display device 30. For example, in the case of a computer device 20 such as a notebook PC or tablet PC, the computer device 20 includes a display device 30.

  Furthermore, the input device 40 is composed of, for example, a keyboard device or a mouse device.

  In the image display system 10, for example, an image based on output image data created using the input device 40 and the computer device 20 is displayed on the display screen 31 of the display device 30. Here, the image display system 10 is required to display an image in a correct color on the display screen 31 of the display device 30. In particular, in the display device 30, the gradation of each of the RGB colors may deviate from the target gradation due to the inherent gradation characteristics of each display device 30. The color of the image will also deviate from the target color.

  Therefore, in this image display system 10, a test image based on test image data created outside the computer device 20 or the computer device 20 is displayed on the display screen 31 using the display device 30 and displayed on the display screen 31. The gradation characteristics (gradation shape) of the display device 30 are estimated based on the image data obtained by photographing the test image, and the gradation correction level is calculated based on the obtained estimation result. A gradation correction operation for creating tone correction data can be executed. In the present embodiment, test image data is created in the computer device 20.

  In FIG. 1, a digital camera 60 used in the gradation correction operation and used for photographing a test image displayed on the display screen 31 of the display device 30 based on the test image data is combined with the image display system 10. Show. Here, the digital camera 60 as an example of the photographing apparatus is built in a mobile phone terminal, a tablet terminal, etc. as well as a dedicated photographing apparatus as long as it can photograph color images using three colors of RGB. It may be a thing. The computer device 20 and the digital camera 60 are connected via, for example, a USB. However, the computer device 20 and the digital camera 60 may be connected via a network. In such a case, a function for creating gradation correction data is assigned to a server connected to the network. (Not shown), and the generated gradation correction data may be returned to the computer apparatus 20.

  Here, the computer apparatus 20 of the present embodiment includes an output image data creation unit 210, a gradation correction unit 220, a test image data storage unit 230, an imaging data processing unit 240, and a target gradation characteristic storage unit 250. A comparison unit 260, a gradation correction data creation unit 270, and a gradation correction data storage unit 280.

  The output image data creation unit 210 as an example of the test image data creation unit creates output image data (including test image data) to be displayed on the display screen 31 using the display device 30, and the gradation correction unit 220. Output to.

  The tone correction unit 220 performs tone correction on the output image data input from the output image data creation unit 210 using the tone correction data read from the tone correction data storage unit 280. The gradation correction unit 220 outputs the obtained gradation-corrected output image data to the display device 30. Note that when the output image data input from the output image data creation unit 210 is, for example, test image data, the gradation correction unit 220 does not perform gradation correction on the output image data, and directly displays the display device 30. Can also be output.

  The test image data storage unit 230 stores original data of various test images used in the gradation correction operation. The test image data storage unit 230 outputs corresponding original data to the output image data creation unit 210 in response to a request from the output image data creation unit 210.

  The imaging data processing unit 240 as an example of the gradation characteristic creating unit acquires imaging data obtained by imaging the display screen 31 using the digital camera 60, and performs a clipping process described later on the acquired imaging data. By performing various image processing including normalization processing, normalization data corresponding to each color of RGB is created. Further, the imaging data processing unit 240 outputs the obtained normalized data of each color of RGB to the comparison unit 260.

  A target gradation characteristic storage unit 250 as an example of a storage unit stores target gradation characteristics (input / output characteristics) of each color of RGB in the display device 30. Further, the target gradation characteristic storage unit 250 outputs the corresponding target gradation characteristic to the comparison unit 260 in response to a request from the comparison unit 260.

  The comparison unit 260 compares the normalized data of each RGB color input from the imaging data processing unit 240 with the target gradation characteristic of each RGB color read from the target gradation characteristic storage unit 250 for each color. Further, the comparison unit 260 outputs an instruction based on the comparison result for each color to the output image data creation unit 210 or the gradation correction data creation unit 270.

  The gradation correction data creation unit 270 as an example of the gradation correction data creation unit, when receiving an instruction from the comparison unit 260, based on the target gradation characteristics of each RGB color and the normalized data of each RGB color, Tone correction data corresponding to each color is created. Also, the gradation correction data creation unit 270 outputs the created gradation correction data to the gradation correction data storage unit 280.

  The gradation correction data storage unit 280 stores the gradation correction data for each of the RGB colors input from the gradation correction data creation unit 270. Further, the gradation correction data storage unit 280 outputs corresponding gradation correction data to the gradation correction unit 220 in response to a request from the gradation correction unit 220.

FIG. 2 is a diagram illustrating a hardware configuration of the computer apparatus 20.
The computer device 20 is realized by a personal computer or the like as described above. As shown in the figure, the computer device 20 includes a CPU (Central Processing Unit) 21 that is arithmetic means, a main memory 22 and an HDD (Hard Disk Drive) 23 that are storage means. Here, the CPU 21 executes various programs such as an OS (Operating System) and application software. The main memory 22 is a storage area for storing various programs and data used for execution thereof, and the HDD 23 is a storage area for storing input data for various programs, output data from various programs, and the like. Further, the computer device 20 includes a communication interface (hereinafter referred to as “communication I / F”) 24 for performing communication with the outside including the input device 40 and the display device 30.

  Note that the output image data creation unit 210, the gradation correction unit 220, the test image data storage unit 230, the imaging data processing unit 240, the target gradation characteristic storage unit 250, the comparison unit 260, and the computer apparatus 20 shown in FIG. The functions of the gradation correction data creation unit 270 and the gradation correction data storage unit 280 are realized by cooperation of software and hardware resources. That is, the CPU 21 provided in the computer device 20 shown in FIG. 2 reads a program for realizing the function of each unit from, for example, the storage device of the HDD 23 into the main memory 22 to realize each of these functions. Further, storage devices such as the HDD 23 and the main memory 22 implement the functions of the test image data storage unit 230, the target gradation characteristic storage unit 250, and the gradation correction data storage unit 280.

  FIG. 3 is a flowchart for explaining the procedure of the gradation correction operation in the image display system 10 of the present embodiment. Note that the following procedure is executed by the computer device 20.

  When receiving an instruction regarding execution of the gradation correction operation via the input device 40 or the like (step 10), the output image data creation unit 210 reads out the original data of the first test image from the test image data storage unit 230 and reads it out. First test image data (output image data) is generated based on the original data, and is output to the display device 30 via the gradation correction unit 220 (step 20). At this time, the gradation correction unit 220 outputs the first test image data input from the output image data creation unit 210 to the display device 30 as it is without performing gradation correction.

  Then, the first test image based on the first test image data input from the computer device 20 is displayed on the display screen 31 by the display device 30. A display image (first display image) including the first test image displayed on the display screen 31 is taken by the digital camera 60.

  Next, the imaging data processing unit 240 acquires first imaging data obtained by the digital camera 60 capturing a first display image including the first test image (step 30). Subsequently, the imaging data processing unit 240 extracts the first test imaging data corresponding to the first test image from the acquired first imaging data (step 40), and further, based on the extracted first test imaging data. First normalization data is created for each color of RGB (step 50).

  Next, the comparison unit 260 acquires the first normalized data of each RGB color from the imaging data processing unit 240, acquires the target gradation characteristics of each RGB color from the target gradation characteristic storage unit 250, and obtains the first normalized data. Is compared with the target gradation characteristic to extract a deviation from the target gradation characteristic of the first normalized data (step 60).

  Then, whether the comparison unit 260 measures more detailed gradation characteristics (referred to as detailed characteristics) in the region extracted from step 60 in the first normalized data where the deviation from the target gradation characteristics is large. It is determined whether or not (step 70). Here, the detailed characteristic means that the input tone value range is narrower than the first normalized data, or the input tone value to be used is the same as the first normalized data and the input tone value range. A value with a large number of values. The determination in step 70 may be performed by the comparison unit 260 itself, or may be based on a user instruction received via the input device 40, for example.

  When an affirmative determination (YES) is made in step 70, the comparison unit 260 outputs an instruction to the output image data creation unit 210. In response to this instruction, the output image data creation unit 210 reads the original data of the second test image from the test image data storage unit 230 and outputs the second test image data (output image data) based on the read original data. It is created and output to the display device 30 via the gradation correction unit 220 (step 80). Here, in step 80, the width and interval of the input gradation value are designated, and the output image data creation unit 210 reads the original data of the second test image corresponding to this designation. At this time, the gradation correction unit 220 outputs the second test image data input from the output image data creation unit 210 to the display device 30 as it is without performing gradation correction.

  Then, the second test image based on the second test image data input from the computer device 20 is displayed on the display screen 31 by the display device 30. A display image (second display image) including the second test image displayed on the display screen 31 is taken by the digital camera 60.

  Next, the imaging data processing unit 240 acquires second imaging data obtained by the digital camera 60 capturing a second display image including the second test image (step 90). Subsequently, the imaging data processing unit 240 extracts the second test imaging data corresponding to the second test image from the acquired second imaging data (step 100), and further, based on the extracted second test imaging data. Then, the second normalized data is created for each color of RGB (step 110).

  Then, the gradation correction data creation unit 270 creates gradation correction data for each color of RGB based on the first normalized data created in step 50 and the second normalized data created in step 110. The created gradation correction data is stored in the gradation correction data storage unit 280 (step 120).

  On the other hand, if a negative determination (NO) is made in step 70, the gradation correction data creation unit 270 creates gradation correction data for each color of RGB based on the first normalized data created in step 50. The created gradation correction data is stored in the gradation correction data storage unit 280 (step 120).

  FIG. 4 is a diagram illustrating an example of the configuration of the first test image 100 used in the gradation correction operation. The first test image 100 is displayed on the display screen 31 by the display device 30 based on the first test image data created in step 20 shown in FIG.

  The first test image 100 shown in FIG. 4 is composed of only the red (R) component of RGB, and each of the red first gradation image R1 and the red second gradation image set to different input gradation values. The green first gradation image G1 and the green second gradation image that are configured only by the green (G) component of R2 and the red third gradation image R3 and RGB, and are set to different input gradation values, respectively. G2 and green third gradation image G3, and blue first gradation image B1 and blue second gradation image which are configured only by the blue (B) component of RGB and are set to different input gradation values, respectively. B2 and blue third gradation image B3, white image W in which each of RGB is set to the highest input gradation value, and black image Bk in which each of RGB is set to the lowest input gradation value It is out. In the present embodiment, the input gradation value of each RGB color is 8 bits, that is, 256 gradations (0 to 255).

  In this example, the input gradation value of the red first gradation image R1 is (R, G, B) = (128, 0, 0), and the input gradation value of the red second gradation image R2 is (R, G, B). G, B) = (160, 0, 0), and the input gradation value of the red third gradation image R3 is set to (R, G, B) = (192, 0, 0). The input gradation value of the green first gradation image G1 is (R, G, B) = (0, 128, 0), and the input gradation value of the green second gradation image G2 is (R, G, B). B) = (0,160,0), and the input gradation value of the green third gradation image G3 is set to (R, G, B) = (0,192,0), respectively. Further, the input gradation value of the blue first gradation image B1 is (R, G, B) = (0, 0, 128), and the input gradation value of the blue second gradation image B2 is (R, G, B). B) = (0,0,160), and the input gradation value of the blue third gradation image B3 is set to (R, G, B) = (0,0,192), respectively. The input gradation value of the white image W is (R, G, B) = (255, 255, 255), and the input gradation value of the black image Bk is (R, G, B) = (0, 0, 0), respectively.

In the first test image 100 shown in FIG. 4, the red first gradation image R1, the red second gradation image R2, and the red third gradation image R3 are arranged side by side in the horizontal direction, and the red first gradation image Below the R1, red second gradation image R2, and red third gradation image R3, the green first gradation image G1, the green second gradation image G2, and the green third gradation image G3 are arranged side by side in the horizontal direction. The blue first gradation image B1, the blue second gradation image B2, and the blue third gradation are below the green first gradation image G1, the green second gradation image G2, and the green third gradation image G3. The image B3 is arranged side by side in the horizontal direction. Accordingly, the red first gradation image R1 to the red third gradation image R3, the green first gradation image G1 to the green third gradation image G3, and the blue first gradation image B1 to blue third gradation. The image B3 is arranged in a 3 × 3 matrix. Further, the white image W is arranged on the left side of the red first gradation image R1, and the black image Bk is arranged below the white image W and on the left side of the green first gradation image G1.
Here, in the present embodiment, the red first gradation image R1 to the red third gradation image R3, the green first gradation image G1 to the green third gradation image G3, and the blue first gradation image B1 to blue. Each of the third gradation image B3, the white image W, and the black image Bk has a function as a test image.
In this embodiment, the black image Bk is the lowest gradation image, the white image W is the highest gradation image, the red first gradation image R1 to the red third gradation image R3, and the green first gradation image. G1 to green third gradation image G3 and blue first gradation image B1 to blue third gradation image B3 function as intermediate gradation images, respectively.

  FIG. 5 is a diagram for explaining the relationship between the display area of the first test image 100 on the display screen 31 and the imaging area 60a by the digital camera 60 (see FIG. 1). Here, FIG. 5A illustrates a display screen 31 having a relatively large screen, and FIG. 5B illustrates a display screen 31 having a relatively small screen.

  In the present embodiment, the first test image 100 is displayed at the center of the display screen 31. Further, the size of the display area of the first test image 100 is set to a common size and smaller than the screen size regardless of the screen size of the display screen 31. The background image constituting the display image together with the first test image 100 is set to black ((R, G, B) = (0, 0, 0)) or gray (gray), for example.

  Further, the size of the imaging region 60 a by the digital camera 60 is set larger than the display region of the first test image 100. In this example, in consideration of the aberration of a lens (not shown) provided in the digital camera 60, the position of the imaging region 60a with respect to the display screen 31 is set so that the peripheral portion of the imaging region 60a becomes a background image. ing. In this example, the imaging region 60 a is set inside the display screen 31. Note that an image such as a frame line indicating the imaging region 60 a may be displayed on the display screen 31 together with the first test image 100.

  FIG. 6 is a diagram for explaining red (R) tone correction based on the first imaging data. More specifically, FIG. 6 is based on the first normalized data obtained from the first imaging data by making a negative determination (NO) in step 70 in the flowchart shown in FIG. The case of creating red gradation correction data is illustrated. 6A shows the target gradation characteristic of red, FIG. 6B shows the first test image data of red, FIG. 6C shows the first normalized data of red, and FIG. d) shows red gradation correction data, respectively. Then, the red target gradation characteristic is stored in the target gradation characteristic storage unit 250, and the red first test imaging data and the red first normalized data are created by the imaging data processing unit 240, and the red gradation correction is performed. The data is created by the gradation correction data creation unit 270.

  In the target red characteristics shown in FIG. 6A, the horizontal axis represents the red input gradation value Rin (0 to 255), and the vertical axis represents the red output gradation value Rout (0 to 255). Show. In this example, the input gradation value and the output gradation value in the red target gradation characteristic are not in a direct proportional relationship indicated by a broken line in the figure, and a gamma curve (for example, γ = 2.2) is drawn. It has become.

  In the first test image data of red shown in FIG. 6B, the horizontal axis indicates the red input gradation value Rin, and the vertical axis indicates the output gradation value Rout before normalization. Show. In this example, the input gradation value and the output gradation value before normalization in the first test image data of red include characteristics unique to the digital camera 60 and the display device 30, respectively. .

  Further, in the first normalized red data shown in FIG. 6C, the horizontal axis indicates the red input gradation value Rin, and the vertical axis indicates the normalized red output gradation value Rout. Yes. In this example, the input gradation value and the normalized output gradation value in the first red normalized data are not directly proportional to each other as indicated by a broken line in the drawing, and a curve unique to the display device 30 is drawn. It is like that.

In the present embodiment, the first red normalized data is obtained through the following procedure.
In the present embodiment, an area corresponding to the first test image 100 from the first imaging data obtained by photographing the display image including the first test image 100 displayed on the display device 30 with the digital camera 60. And the first test imaging data is obtained. Then, from the obtained first test imaging data, as shown in FIG. 6B, a red first output tone value r1 that is a red output tone value of an area corresponding to the red first tone image R1. A red second output tone value r2 that is a red output tone value of the region corresponding to the red second tone image R2, and a red output tone value of the region corresponding to the red third tone image R3. The red third output tone value r3, the red maximum output tone value rmax that is the red output tone value of the region corresponding to the white image W, and the red output tone of the region corresponding to the black image Bk The red minimum output gradation value rmin that is a value is extracted. Then, as shown in FIG. 6C, the red first output tone value r1 and the red second output tone value rmin are set to 0, and the red maximum output tone value rmax is set to 1. The output gradation value r2 and the red third output gradation value r3 are normalized. Thereafter, by drawing an approximate curve connecting the five normalized points (rmin, r1, r2, r3, rmax), red first normalized data is obtained.

  In the first normalized red data thus obtained, the red first output tone value r1 to the red third output tone value r3 are obtained as relative values rather than absolute values. Each digital camera 60 has unique device characteristics, and various automatic adjustments may be performed at the time of shooting or may be affected by lighting. By performing such normalization, In the first normalized data of red, it is possible to reduce the influence of device characteristics and the like unique to the digital camera 60.

  Furthermore, the red tone correction data shown in FIG. 6D is obtained by inverting the first red normalized data shown in FIG. The obtained red tone correction data is stored in the tone correction data storage unit 280, and thereafter used for tone correction of the output image data by the tone correction unit 220.

  Although details are not described here, the green gradation correction based on the first imaging data and the blue gradation correction based on the first imaging data are also performed on the red floor based on the first imaging data described above. The same procedure as the tone correction is executed, and as a result, green tone correction data and blue tone correction data are obtained.

  FIG. 7 is a diagram showing an example of the configuration of the second test image 200 used in the gradation correction operation. The second test image 200 is displayed on the display screen 31 by the display device 30 based on the second test image data created in step 80 shown in FIG. Note that here, when the detailed characteristics are measured before and after the red third gradation image R3 because the deviation of the red third gradation image R3 is larger than the target gradation characteristics (steps shown in FIG. 3). A second test image 200 of “YES” in 70) is illustrated.

  The second test image 200 shown in FIG. 7 is composed of only the red (R) component of RGB, and each of the red third gradation image R3 and the red fourth gradation image R4 set to different input gradation values. , A red fifth gradation image R5, a red sixth gradation image R6, and a red seventh gradation image R7, and four gray images Gr in which RGB are set to intermediate input gradation values, respectively.

  In this example, the input gradation value of the red third gradation image R3 is set to (R, G, B) = (192, 0, 0) as described in the first test image 100. In contrast, the input gradation value of the red fourth gradation image R4 is (R, G, B) = (176, 0, 0), and the input gradation value of the red fifth gradation image R5 is (R, G, B). G, B) = (208, 0, 0), the input gradation value of the red sixth gradation image R6 is (R, G, B) = (224, 0, 0), the red seventh gradation image The input gradation value of R7 is set to (R, G, B) = (240, 0, 0), respectively. The input grayscale values of the four gray images Gr are set to (R, G, B) = (128, 128, 128), respectively.

In the second test image 200 shown in FIG. 7, the red fourth gradation image R4, the first gray image Gr, and the red fifth gradation image R5 are arranged side by side in the horizontal direction. R4, the second gray image Gr, the red third gradation image R3, and the third gray image Gr are arranged in the horizontal direction below the first gray image Gr and the red fifth gradation image R5. The red sixth gradation image R6, the fourth gray image Gr, and the red seventh gradation are below the second gray image Gr, the red third gradation image R3, and the third gray image Gr. The image R7 is arranged side by side in the horizontal direction. Accordingly, a total of nine images are arranged in a 3 × 3 matrix. In this example, red images and gray images are alternately arranged in the vertical direction and the horizontal direction.
Here, in the present embodiment, each of the red fourth gradation image R4 to the red seventh gradation image R7 and the four gray images Gr also has a function as a test image.

  FIG. 8 is a diagram for explaining red (R) tone correction based on the first imaging data and the second imaging data. More specifically, FIG. 8 shows the first normalized data and the second imaging obtained from the first imaging data by making a positive determination (YES) in step 70 in the flowchart shown in FIG. The case where red gradation correction data is created based on the second normalized data obtained from the data is illustrated. Here, FIG. 8A shows the target gradation characteristic of red, FIG. 8B shows the first test image data of red and the second test image data of red, and FIG. 8C shows the first test image of red. FIG. 8D shows the normalized data and the second red normalized data, and FIG. 8D shows the red gradation correction data. Then, the red target gradation characteristic is stored in the target gradation characteristic storage unit 250, and the red first test imaging data, the red second test imaging data, the red first normalization data, and the red second normalization. Data is created by the imaging data processing unit 240, and red tone correction data is created by the tone correction data creation unit 270. Here, the red target gradation characteristic shown in FIG. 8A is the same as that shown in FIG.

  In the red first test image data and the second test image data shown in FIG. 8B, the horizontal axis indicates the red input gradation value Rin, and the vertical axis indicates the output before normalization. The gradation value Rout is shown. In this example, the input tone value and the output tone value before normalization in the first test image data and the second test image data of red are characteristics specific to the digital camera 60 and the display device 30, respectively. Is included.

  Further, in the red first normalized data and the red second normalized data shown in FIG. 8C, the horizontal axis indicates the red input gradation value Rin, and the vertical axis indicates the normalized red color. The output gradation value Rout is shown. In this example, the input gradation value and the normalized output gradation value in the first red normalized data are not directly proportional to each other as indicated by a broken line in the drawing, and a curve unique to the display device 30 is drawn. It is like that.

In the present embodiment, the second red normalized data is obtained through the following procedure.
In the present embodiment, an area corresponding to the second test image 200 from the second imaging data obtained by photographing the display image including the second test image 200 displayed on the display device 30 with the digital camera 60. To obtain second test imaging data. Then, from the obtained second test imaging data, a red third output gradation value r3 that is a red output gradation value in a region corresponding to the red third gradation image R3, and a red fourth gradation image R4. The red fourth output tone value r4, which is the red output tone value of the corresponding region, and the red fifth output tone value r5, which is the red output tone value of the region corresponding to the red fifth tone image R5. A red sixth output tone value r6 that is a red output tone value of the region corresponding to the red sixth tone image R6, and a red output tone value of the region corresponding to the red seventh tone image R7. The red seventh output gradation value r7 is extracted. Then, using the red third output tone value r3, the red fourth output tone value r4, the red fifth output tone value r5, the red sixth output tone value r6, and the red seventh output tone value. The value r7 is normalized. Here, the red third gradation image R3 is an image included in both the first test image 100 and the second test image 200, and by performing such normalization, the red fourth gradation image R4 is converted into the red fourth gradation image R4. The red seventh output tone value r7 corresponding to the corresponding red fourth output tone value r4 to the red seventh tone image R7 is the red first output tone value r1 corresponding to the red first tone image R1. Normalization is performed under the same conditions as the red third output gradation value r3. Then, by drawing an approximate curve connecting the nine normalized points (rmin, r1, r2, r3, r4, r5, r6, r7, rmax), the first normalized data for red and the second normalized for red Data is obtained.

  In the first red normalized data and the second red normalized data thus obtained, the red first output tone value r1 to the red seventh output tone value r7 are not absolute values but relative values. Is obtained as a correct value. Each digital camera 60 has unique device characteristics, and various automatic adjustments may be performed at the time of shooting. By performing such normalization, the red first normalized data and In the red second normalized data, it is possible to reduce the influence of device characteristics and the like unique to the digital camera 60.

Furthermore, the red tone correction data shown in FIG. 8D is obtained by inverting the first red normalized data and the second red normalized data shown in FIG. 8C. The obtained red tone correction data is stored in the tone correction data storage unit 280, and thereafter used for tone correction of the output image data by the tone correction unit 220.
Compared with the example shown in FIG. 6D, the red tone correction data obtained at this time becomes more accurate as the number of measurement points increases.

  Although details are not described here, the green gradation correction based on the first imaging data and the second imaging data and the blue gradation correction based on the first imaging data and the second imaging data are also described above. The same procedure as the red gradation correction based on the first imaging data and the second imaging data is performed, and as a result, green gradation correction data and blue gradation correction data are obtained.

DESCRIPTION OF SYMBOLS 10 ... Image display system, 20 ... Computer apparatus, 30 ... Display apparatus, 31 ... Display screen, 40 ... Input device, 60 ... Digital camera, 60a ... Imaging area, 100 ... 1st test image, 200 ... 2nd test image, 210: output image data creation unit, 220: gradation correction unit, 230: test image data storage unit, 240: imaging data processing unit, 250: target gradation characteristic storage unit, 260: comparison unit, 270: gradation correction data Creation unit, 280 ... gradation correction data storage unit

Claims (4)

Test image data creating means for creating test image data for displaying a test image including a plurality of images having different input gradation values on the display screen of the display device;
The test image data and the previous SL test image displayed on the display screen acquires imaging data obtained by photographing by the photographing apparatus based on, on each of a plurality of images of those the test image that put on the imaging data A gradation characteristic creating means for creating a relative gradation characteristic of the display device based on a plurality of corresponding output gradation values;
Look including the gradation correction data generation means for generating tone correction data for correcting output characteristics of the display device based on the relative gradation characteristic,
The test image data creation means is configured to display the test image including a plurality of images each composed of R (red), G (green), and B (blue) color components and having different input tone values. Creating the test image data;
The gradation characteristic creating means obtains the imaging data and creates the relative gradation characteristic for each color of RGB,
The tone correction data creating means creates tone correction data for each color of RGB . The test image data creating means includes a lowest gradation image with the lowest input gradation value, a highest gradation image with the highest input gradation value, an input gradation value with the lowest gradation image, and the highest order image. Creating the test image data including, as the test image, an intermediate gradation image between the tone image and
The gradation characteristic creating means normalizes the output gradation value of the intermediate gradation image using the output gradation value of the lowest gradation image and the output gradation value of the highest gradation image in the imaging data. The gradation correction apparatus according to claim 1, wherein the relative gradation characteristic is created. And further comprising storage means for storing target gradation characteristics in the display device,
2. The gradation correction data creation means creates the gradation correction data based on the relative gradation characteristics and the target gradation characteristics read from the storage means. Or the gradation correction apparatus of 2. On the computer,
A function of creating test image data for displaying a test image including a plurality of images having different input gradation values on the display screen of the display device;
It acquires imaging data obtained by photographing by the photographing apparatus pre-Symbol test image displayed on the display screen based on the test image data, to each of a plurality of images before Symbol test images that put on the imaging data A function of creating relative gradation characteristics of the display device based on a plurality of corresponding output gradation values;
A function of creating gradation correction data for correcting input / output characteristics of the display device based on the relative gradation characteristics ;
The function of creating the test image data is composed of R (red), G (green), and B (blue) color components, and displays the test image including a plurality of images having different input gradation values. Creating the test image data for
The function of creating the gradation characteristics acquires the imaging data and creates the relative gradation characteristics for each color of RGB,
The function for creating the gradation correction data is a program for creating gradation correction data for each color of RGB .

Images