Image processing apparatus, and image processing method

Abstract

To provide a look-up table adjustment technique for reducing the occurrence of gradation collapse.SOLUTION: An image processing apparatus defines, of lattice points in a look-up table for color conversion, a lattice point corresponding to a pixel value of a pixel position designated according to a user operation as an adjustment target lattice point, and determines whether adjustment of the color value of the adjustment target lattice point according to a user operation causes the occurrence of gradation collapse on the basis of lattice points in the look-up table after the adjustment. When determining that the gradation collapse occurs, the image processing apparatus re-adjusts the look-up table after the adjustment.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to image processing technology. [Background technology]

[0002] Conventionally, there have been systems for broadcasting live television programs and sports broadcasts that use multiple imaging devices (cameras) to capture images and mix and broadcast the images. In such systems, for example, in a sports broadcast, one camera captures an overhead image of the entire game venue, while other cameras capture images of the players from various positions to broadcast the game. In such cases, it is common to use multiple types of cameras to capture images.

[0003] However, when using multiple models of cameras, the manufacturers and grades of the cameras are often different, and the images produced by these cameras can differ greatly from one another. As a result, even if the same subject is being shot, the color of the subject can change when the camera is switched. This requires the camera operator and video engineer (VE) to adjust the cameras before broadcasting so that the colors are the same between the cameras, which is a huge burden.

[0004] To solve such problems, for example, Patent Document 1 proposes a technique in which the same subject is captured by each camera and color differences between the captured images are corrected. It is also known that the correction parameters created using the technique shown in Patent Document 1 cause differences in color conversion accuracy between the cameras depending on the color. For this reason, a method has been proposed in which color conversion parameters are adjusted while viewing the image during conversion using the technique shown in Patent Document 2. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-9162 A [Patent Document 2] Patent No. 3890211 Summary of the Invention [Problem to be solved by the invention]

[0006] In the above conventional technology, color conversion parameters can be adjusted for parts of the currently displayed image that need to be matched with high accuracy. However, the influence of the adjustment when the content of the image changes is not taken into consideration. In particular, when performing color conversion using a three-dimensional lookup table (3DLUT), if the adjustment is made without considering the order between the lattice points when adjusting the lattice points that make up the 3DLUT, gradation breakdown may occur. Since the likelihood of this gradation breakdown differs depending on the type of image, there is a problem that it is difficult to adjust the 3DLUT so as not to cause gradation breakdown when the 3DLUT is adjusted based only on a specific image. The present invention provides a lookup table adjustment technology that is less likely to cause gradation breakdown. [Means for solving the problem]

[0007] One aspect of the present invention is characterized in that it comprises a determination means for determining, as an adjustment target lattice point, among lattice points in a lookup table for color conversion, a lattice point corresponding to a pixel value at a pixel position specified in response to user operation, and determining, based on the lattice point in the adjusted lookup table, whether or not a gradation breakdown will occur as a result of adjusting the color value of the adjustment target lattice point in response to user operation, and an adjustment means for readjusting the adjusted lookup table if it is determined that the gradation breakdown will occur. Effect of the Invention

[0008] According to the present invention, it is possible to provide a lookup table adjustment technique that is less likely to cause gradation breakdown. [Brief description of the drawings]

[0009] [Figure 1]FIG. 1 is a diagram showing an example of a system configuration. [Diagram 2] FIG. 2 is a block diagram showing an example of the hardware configuration of a computer device applicable to a controller 300. [Diagram 3] FIG. 2 is a block diagram showing an example of the functional configuration of a controller 300. [Figure 4] 4 is a flowchart of a process performed by a controller 300. [Diagram 5] 11A and 11B are diagrams showing examples of display of a captured image and an adjustment image after color conversion. [Figure 6] FIG. 13 is a diagram showing an example of a GUI display. [Figure 7] FIG. 11 is a diagram showing a display example of notification information. [Figure 8] FIG. 13 is a diagram showing an example used to explain the details of the determination process in step S406. [Figure 9] 4 is a flowchart of a process performed by a controller 300. [Figure 10] FIG. 11 is a diagram showing an example of an image of a gradation chart. [Figure 11] FIG. 1 is a diagram showing an example of a system configuration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0011] [First embodiment] In this embodiment, a system is described that adjusts "a lookup table (LUT) for converting a first color of a subject in an image captured by one camera to a second color so that the first color matches the second color of the subject in an image captured by the other camera." The subject is, for example, a color chart. Such an LUT is, for example, an LUT created in advance using a well-known technique such as that described in Patent Document 1.

[0012] First, a configuration example of a system according to this embodiment will be described with reference to Fig. 1. As shown in Fig. 1, a system 1000 according to this embodiment has a camera 100A, a camera 100B, and a controller 300, and the camera 100A, the camera 100B, and the controller 300 are all connected to a network 400. The network 400 includes a plurality of routers, switches, cables, etc., conforming to a communication standard such as EtherNet (registered trademark). Note that the communication standard, scale, and configuration of the network 400 are not limited to a specific communication standard, scale, and configuration, as long as the network 400 is a network that enables data communication between the cameras 100A and 100B and the controller 300.

[0013] Each of the cameras 100A and 100B includes a lens group constituting an imaging optical system, an imaging element such as a CMOS, an image processing circuit that performs various image processing, etc. The lens group has a plurality of optical lenses, and incident light from the outside enters the imaging element through the lens group, and the imaging element performs photoelectric conversion of the incident light and outputs an image signal. The image processing circuit performs demosaic processing and various color correction processing based on the image signal to generate a captured image, and outputs the generated captured image.

[0014] Camera 100A and camera 100B may be cameras that capture moving images, or may be cameras that capture still images periodically or irregularly. When camera 100A / camera 100B captures moving images, it outputs images of each frame in the moving images as captured images. On the other hand, when camera 100A / camera 100B captures still images periodically or irregularly, it outputs the still images as captured images.

[0015] In this embodiment, a camera that can capture the target color to be matched is referred to as a primary camera, and a camera to be corrected so that it can capture the same color as the primary camera is referred to as a camera to be subjected to color correction. In the following description, camera 100A is referred to as the primary camera, and camera 100B is referred to as the camera to be subjected to color correction.

[0016] The controller 300 is a computer device that functions as an image processing device, such as a personal computer (PC), a smartphone, or a tablet PC. The controller 300 acquires images captured by the camera 100A or the camera 100B via the network 400, performs various image processing on the acquired captured images, and performs setting processing on the camera 100A or the camera 100B. The controller 300 also generates and adjusts the above-mentioned LUT. A functional configuration example of the controller 300 is shown in the block diagram of FIG. 3. The configuration shown in FIG. 3 is an example of a configuration for determining whether or not a gradation breakdown occurs for an LUT adjusted according to a user operation, and re-adjusting the LUT within a range in which a gradation breakdown does not occur when it is determined that a gradation breakdown occurs. The process performed by the controller 300 in such a configuration will be described with reference to the flowchart of FIG. 4.

[0017] In step S401, adjustment unit 303 acquires the LUT stored in storage unit 302. The LUT is "an LUT for converting a second color into a first color so that the color (first color) of a subject in an image captured by camera 100A matches the color (second color) of the subject in an image captured by camera 100B."

[0018] In step S402, the input unit 301 acquires the captured image output from the camera 100A and the captured image (adjustment image) output from the camera 100B. The conversion unit 304 converts the color of the adjustment image (color conversion) using the LUT acquired by the adjustment unit 303 in step S401. The color conversion may be performed using a known color conversion method such as tetrahedral interpolation or cubic interpolation. The display unit 305 displays the captured image output from the camera 100A and the color-converted adjustment image on a display screen. The display screen may be a display screen of the controller 300, or may be a display screen of a device separate from the controller 300.

[0019] An example of the display of a captured image and a color-converted adjustment image on a display screen is shown in Fig. 5. A captured image of subject 503 output from camera 100A is displayed as a reference camera image in window 501. Also, a color-converted adjustment image of subject 503 is displayed as a color-converted camera image in window 502.

[0020] The user looks at this display screen and specifies, through user operation, the pixel position at which the color of the captured image displayed in window 501 is to be adjusted in the "adjustment image after color conversion" displayed in window 502. For example, as shown in Fig. 5, the user can use the mouse to move cursor 505 to the desired pixel position and double-click there to specify that pixel position as the adjustment pixel position.

[0021] In step S403, the designation unit 306 acquires an adjustment pixel position designated in response to a user operation. In step S404, the determination unit 307 acquires a pixel value (e.g., RGB value) of a pixel at an adjustment pixel position in an adjustment image acquired from the camera 100B. The determination unit 307 then obtains an L*a*b* value, which is a color value corresponding to the pixel value, in the color space (L*a*b* color space) of the LUT. The determination unit 307 then identifies a lattice point group that surrounds (contains) the L*a*b* value among the lattice points in the LUT in the L*a*b* color space, and identifies a lattice point that is closest to the L*a*b* value among the identified lattice points as an adjustment target lattice point. The determination unit 307 then displays a GUI (Graphical User Interface) on the display screen for adjusting the L*a*b* value corresponding to the adjustment target lattice point in response to a user operation.

[0022] In step S405, the designation unit 309 accepts a user operation on the GUI, and the adjustment unit 303 adjusts (corrects) the L* value, a* value, and b* value corresponding to the lattice point to be adjusted in the LUT in response to the user operation. An example of a GUI display is shown in Fig. 6. The designation unit 309 accepts a user operation on the GUI 601, and the adjustment unit 303 controls the display of the GUI 601 and performs all processing in response to the user operation on the GUI 601.

[0023] In the GUI 601, buttons 606, 607, 608, and 609 and an area 605 are provided for the L* value. Similar buttons and areas are provided for the a* value and the b* value, respectively. The buttons 606, 607, 608, and 609 and the area 605 provided for the L* value will be described below.

[0024] In area 605, the L* value corresponding to the lattice point to be adjusted is displayed. Each time the user operates the mouse or the like to move cursor 603 to the position of button 606 and clicks there, the L* value of the lattice point to be adjusted is decreased by 1.0, and area 605 displays the L* value of the lattice point to be adjusted after the decrease. Each time the user operates the mouse or the like to move cursor 603 to the position of button 607 and clicks there, the L* value of the lattice point to be adjusted is decreased by 0.1, and area 605 displays the L* value of the lattice point to be adjusted after the decrease. Each time the user operates the mouse or the like to move cursor 603 to the position of button 608 and clicks there, the L* value of the lattice point to be adjusted is increased by 0.1, and area 605 displays the L* value of the lattice point to be adjusted after the increase. Each time the user operates the mouse or the like to move cursor 603 to the position of button 609 and clicks there, the L* value of the lattice point to be adjusted is increased by 1.0, and area 605 displays the L* value of the lattice point to be adjusted after the increase. The same explanation applies to the a* and b* values. In this way, the user can adjust the L*, a*, and b* values ​​of the grid point to be adjusted via the GUI 601. When the user then operates the mouse or the like to move the cursor 603 to the position of the completed button 604 and clicks it, the process proceeds to step S406.

[0025] Note that, although an example of a method of operating GUI601 has been described here, it is not limited to a specific operating method, and the GUI for adjusting the L*a*b* values ​​corresponding to the lattice points to be adjusted in response to user operations is not limited to GUI601, and GUIs of various configurations can be applied.

[0026] Next, in step S406, the determination unit 310 determines whether or not a gradation breakdown occurs in the adjusted LUT. If it is determined that a gradation breakdown occurs as a result of this determination, the process proceeds to step S407, and if it is determined that a gradation breakdown does not occur, the process proceeds to step S410. Here, the details of the determination process in step S406 will be described using FIG. 8 as an example.

[0027] FIG. 8 shows a part of the lattice point group in the LUT. As shown in FIG. 8(a), it is known that if the anteroposterior relationship of the lattice points in the LUT is maintained, gradation failure does not occur. However, as shown in FIG. 8(b), as a result of adjusting the lattice point positions (L*a*b* values) in the LUT, a shift may occur, for example, such that the anteroposterior relationship of the lattice point positions is reversed. Due to this shift, the monotonous increase of pixel values ​​is not guaranteed, and gradation failure such as gradation inversion is likely to occur. Therefore, in step S406, the determination unit 310 determines whether or not a shift has occurred in the positional relationship of the lattice points, and if a shift has occurred, it determines that a gradation failure will occur, and if no shift has occurred, it determines that a gradation failure will not occur.

[0028] In order to determine whether or not a shift has occurred in the relationship between the positions of the lattice points, the inner product and the cross product of the vectors between the lattice points in the LUT are used. For example, when the positions of 27 lattice points in a 9-slice 3D LUT are A[0][0][0] to A[8][8][8], and l, m, and n are 0 to 8, the determining unit 310 calculates the following (Equation 1) to (Equation 6) for a tetrahedron consisting of the positions of eight adjacent lattice points: A[l][m][n], A[l+1][m][n], A[l][m+1][n], A[l][m][n+1], A[l+1][m+1][n], A[l+1][m][n+1], A[l][m+1][n+1], A[l+1][m+1][n+1], A[l+1][m+1][n+1], A[l+1][m+1][n+1].

[0029]

number

[0030]

number

[0031]

number

[0032]

number

[0033]

number

[0034]

number

[0035] Then, if any of the calculation results of equations (1) to (6) are positive, the judgment unit 310 judges that a gradation breakdown will not occur, and if any of the calculation results of equations (1) to (6) are negative, the judgment unit 310 judges that a gradation breakdown will occur.

[0036] In step S407, the determination unit 308 adjusts (corrects) the L*a*b* value of the adjustment target grid point in the LUT to an L*a*b* value that does not cause gradation failure. Specifically, the determination unit 308 corrects the adjustment value (one or more of the L* value, a* value, and b* value) adjusted in step S405 to a smaller adjustment value. Then, the determination unit 308 performs a judgment similar to that in step S406 for the corrected LUT to determine whether or not gradation failure occurs in the LUT. If it is determined that gradation failure occurs as a result of the judgment, the determination unit 308 again corrects the adjustment value to a smaller adjustment value and performs a judgment similar to that in step S406 for the corrected LUT to determine whether or not gradation failure occurs in the LUT. For example, if the L* value in the GUI 601 is increased by 1.0 from before the adjustment, the L* value is increased by 0.5 from before the adjustment, and then it is determined whether or not gradation failure occurs. If it is determined that gradation failure will occur as a result of this determination, the L* value is corrected to a value increased by 0.1 from before adjustment, and then it is determined whether or not gradation failure will occur. If it is determined that gradation failure will occur as a result of this determination, it is determined whether or not gradation failure will occur for the LUT before correction of the adjustment value.

[0037] In this way, the determining unit 308 corrects (updates) the LUT so that no gradation breakdown occurs by correcting the L*a*b* values ​​of the adjustment target lattice points so that no gradation breakdown occurs.

[0038] In step S408, the display unit 311 displays, on the display screen, notification information for notifying the user of the result of the adjustment by the determination unit 308 as a warning display. For example, if the user performs an operation in the GUI 601 to increase the L* value by 1.0 from before the adjustment and corrects the L* value to a value increased by 0.5 from before the adjustment in step S407, the display unit 311 displays, on the display screen, notification information indicating that, as shown in FIG.

[0039] In step S410, the conversion unit 304 converts the color of the adjustment image acquired from the camera 100B using the LUT, and the display unit 305 displays the color-converted adjustment image on the display screen. When the process advances from step S406 to step S410, the conversion unit 304 uses the LUT adjusted in step S405. On the other hand, when the process advances from step S408 to step S410, the conversion unit 304 uses the LUT adjusted in step S407.

[0040] In step S411, the control unit 390 determines whether or not an adjustment end condition is satisfied. Various conditions can be applied as the adjustment end condition. For example, the user inputs an adjustment end command using a keyboard or mouse, the power of the camera 100A or the camera 100B is turned off, etc.

[0041] If it is determined that the adjustment end condition is satisfied, the process proceeds to step S412; if the adjustment end condition is not satisfied, the process proceeds to step S403.

[0042] In step S412, the output unit 312 stores the LUT (the LUT adjusted in step S405 if the process proceeds from step S406 to step S410, or the LUT adjusted in step S407 if the process proceeds from step S408 to step S410) in the holding unit 302. The output unit 312 may also transmit the LUT to the camera 100B. In this case, the camera 100B performs color conversion on the image captured by itself using the LUT and then transmits the image to the controller 300.

[0043] As described above, according to this embodiment, when adjusting the LUT for color conversion between cameras, it is possible to adjust the LUT in a way that is less likely to cause gradation breakdown, regardless of the content of the image captured by the camera.

[0044] The configuration shown in Fig. 3 can be modified / altered as appropriate. For example, one functional unit may be divided into multiple functional units according to function, or two or more functional units may be integrated into one functional unit. The configuration in Fig. 3 may be configured by two or more devices. In this case, the devices are connected via a circuit or a wired or wireless network, and perform data communication with each other to operate cooperatively, thereby realizing each process described as the process performed by the controller 300.

[0045] [Second embodiment] The following describes the differences from the first embodiment, and unless otherwise specified below, it is assumed that the present embodiment is the same as the first embodiment. In this embodiment, the processes in steps S407 and S408 are not performed, and the user is notified of the color conversion result that will be obtained when color conversion is performed using the LUT obtained by the adjustment in step S405.

[0046] The process performed by the controller 300 according to this embodiment will be described with reference to the flowchart of Fig. 9. In Fig. 9, the same process steps as those shown in Fig. 4 are assigned the same step numbers, and the description of these process steps will be omitted.

[0047] If it is determined in step S406 that gradation breakdown will occur, the process proceeds to step S413, and if it is determined that gradation breakdown will not occur, the process proceeds to step S410.

[0048] In step S413, the display unit 305 converts the color of the adjustment image acquired from the camera 100B using the LUT adjusted in step S405, and acquires the image obtained by the color conversion as a first image. The display unit 305 also converts the color of a test image previously stored in the controller 300 using the LUT adjusted in step S405, and acquires the image obtained by the color conversion as a second image. For example, an image of a gradation chart as exemplified in FIG. 10 can be applied to the test image. The display unit 305 then displays the first image and the second image on the display screen.

[0049] By visually checking the first and second images displayed on the display screen, the user can determine whether there is a gradation breakdown or whether further adjustment of the LUT is necessary, thereby allowing the user to determine a preferred adjustment value.

[0050] In this way, according to this embodiment, it is possible to present to the user the color conversion results using the current LUT, which makes it possible to adjust the LUT in a way that is less likely to cause gradation breakdown, for example.

[0051] [Third embodiment] As a system having a different configuration from the system according to the first embodiment, image processing devices 200A and 200B may be added as shown in Fig. 11(a). The image processing device 200A acquires a captured image output from the camera 100A, converts the color of the captured image using the LUT, and outputs the color-converted captured image to the controller 300 via the network 400. The image processing device 200B acquires a captured image output from the camera 100B, converts the color of the captured image using the LUT, and outputs the color-converted captured image to the controller 300 via the network 400. In this case, the settings such as the recording mode of each camera may be acquired via the image processing device 200A, or the cameras may be connected to the network 400.

[0052] 11(b), the controller 300 may be mounted on the cameras 100A and 100B. The camera 100A has a monitor 1001 having a liquid crystal screen or a touch panel screen, and an operation unit 1002 having a group of buttons. The camera 100B has a monitor 1003 having a liquid crystal screen or a touch panel screen, and an operation unit 1004 having a group of buttons. The controller 300 mounted on the camera adjusts the LUT as described above based on the captured image captured by the camera, and performs color conversion on the captured image captured by the camera using the LUT.

[0053] [Fourth embodiment] In the first embodiment, the functional units (excluding the storage unit 302) shown in Fig. 3 are implemented in hardware, but the functional units (excluding the storage unit 302) shown in Fig. 3 may be implemented in software (computer program). In this case, a computer device capable of executing this computer program is applicable to the controller 300. An example of the hardware configuration of a computer device applicable to the controller 300 will be described with reference to the block diagram of Fig. 2.

[0054] The CPU 201 executes various processes using computer programs and data stored in the RAM 202. As a result, the CPU 201 controls the operation of the entire computer device, and executes or controls the various processes described as the processes performed by the controller 300.

[0055] The RAM 202 has an area for storing computer programs and data loaded from the ROM 203, the HDD 205, or the external storage device 209, and an area for storing data received from the outside via the network I / F 212. The RAM 202 also has a work area used when the CPU 201 executes various processes. In this way, the RAM 202 can provide various areas as needed.

[0056] The ROM 203 stores setting data for the computer device, computer programs and data related to the startup of the computer device, computer programs and data related to the basic operation of the computer device, and the like.

[0057] The HDD 205 is connected to the auxiliary storage I / F 204. The HDD 205 stores an OS (operating system), computer programs and data for making the CPU 201 execute or control various processes described as processes performed by the controller 300, and the like. The computer programs stored in the HDD 205 include computer programs for making the CPU 201 realize the functions of the functional units (excluding the storage unit 302) shown in FIG. 3. The data stored in the HDD 205 includes information and LUTs described as known information. The computer programs and data stored in the HDD 205 are loaded into the RAM 202 as appropriate under the control of the CPU 201, and are processed by the CPU 201. The computer device may have various storage devices such as an optical disk drive and a flash memory in addition to or instead of the HDD 205.

[0058] The input I / F 206 is, for example, a serial bus interface such as USB or IEEE1394, and an operation device 211 and an external storage device 209 are connected to the input I / F 206. The operation device 211 is a user interface such as a keyboard, a mouse, a touch panel screen, etc., and can be operated by a user to input various instructions and information to the computer device. For example, the user can operate the operation device 211 to specify the adjustment pixel position or to operate the GUI.

[0059] The external storage device 309 reads and writes computer programs and data from and to a storage medium such as a memory card, a CF card, an SD card, a USB memory, etc. A part or all of the computer programs and data described as being saved in the HDD 205 may be stored in the storage medium, and the external storage device 209 may read the computer programs and data from the storage medium to the RAM 202. The holding unit 302 in Fig. 3 can be implemented using a memory device such as the RAM 202, the HDD 205, or the external storage device 209.

[0060] The output I / F 207 is a serial bus interface such as USB or IEEE1394, similar to the input I / F 206, and a display device 210 is connected to the output I / F 207. The output I / F 207 may be a video output terminal such as DVI or HDMI (registered trademark).

[0061] The display device 210 has a liquid crystal screen or a touch panel screen, and can display the results of processing by the CPU 201 as images, characters, etc. The display screen in the above description may be a display screen that the display device 210 has.

[0062] The network I / F 212 is a connector or the like for connecting to a network such as Ethernet. The network I / F 212 enables the computer device to perform data communication with external devices (camera 100A and camera 100B in the example of FIG. 1) on the network 400 via the network I / F 212.

[0063] The CPU 201 , RAM 202 , ROM 203 , auxiliary storage I / F 204 , input I / F 206 , output I / F 207 , and network I / F 212 are all connected to a system bus 208 .

[0064] The numerical values, processing timing, processing order, processing subject, color space, data (information) acquisition method / destination / source / storage location, etc. used in each of the above embodiments are given as examples to provide a concrete explanation, and are not intended to be limited to these examples.

[0065] In addition, a part or all of the embodiments described above may be used in appropriate combination. In addition, a part or all of the embodiments described above may be used selectively.

[0066] (Other embodiments) The present disclosure can also be realized by a process in which a program for implementing one or more functions of the above-described embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more functions.

[0067] The invention of this specification includes the following image processing device, image processing method, and computer program. (Item 1) a determination means for determining whether or not a gradation breakdown occurs as a result of adjusting the color value of the adjustment target lattice point in accordance with the user's operation, based on the lattice point in the lookup table after the adjustment; and an adjustment means for readjusting the adjusted lookup table when it is determined that the gradation breakdown will occur; An image processing device comprising: (Item 2) 2. The image processing device according to item 1, wherein the determination means determines, as an adjustment target lattice point, a lattice point in the lookup table that is closest to a color value corresponding to the pixel value among the lattice points surrounding the color value corresponding to the pixel value. (Item 3) 3. The image processing device according to item 1 or 2, wherein the lookup table is a lookup table for converting a color of a first image captured by a first camera into a color of a second image captured by a second camera. (Item 4) The image processing device described in item 3 is characterized in that the determination means acquires a pixel position specified in response to a user operation on the first captured image after color conversion in which the first captured image is color converted using the lookup table, and sets a lattice point in the lookup table that corresponds to a pixel value of the pixel position of the first captured image as an adjustment target lattice point. (Item 5) The image processing device described in any one of items 1 to 4, characterized in that the judgment means uses vectors between adjacent lattice points in the adjusted lookup table to judge whether or not a gradation breakdown occurs due to an inversion of the front-to-back relationship of the positions of the lattice points in the adjusted lookup table. (Item 6) 6. The image processing device according to any one of items 1 to 5, wherein the adjustment means adjusts the color values ​​of the adjustment target lattice points so that gradation breakdown does not occur. (Item 7) 7. The image processing device according to any one of items 1 to 6, wherein the adjustment means displays a result of the adjustment by the adjustment means on a display screen. (Item 8) 8. The image processing device according to any one of items 1 to 7, wherein the lattice points in the lookup table are lattice points in an L*a*b* color space. (Item 9) moreover, 9. The image processing device according to any one of items 1 to 8, further comprising a display unit for displaying a result of color conversion using the lookup table adjusted by the adjustment unit. (Item 10) moreover, An imaging means; a color conversion means for converting a color of the captured image captured by the imaging means using the lookup table adjusted by the adjustment means; 10. The image processing device according to any one of items 1 to 9, comprising: (Item 11) An image processing method performed by an image processing device, comprising: a judgment step in which a judgment means of the image processing device determines, among lattice points in a lookup table for color conversion, a lattice point corresponding to a pixel value at a pixel position designated in response to a user operation as an adjustment target lattice point, and judges whether or not a gradation breakdown occurs as a result of adjusting the color value of the adjustment target lattice point in response to the user operation, based on the lattice point in the lookup table after the adjustment; an adjustment step in which, when it is determined that the gradation breakdown occurs, the adjustment means of the image processing device readjusts the lookup table after the adjustment; An image processing method comprising: (Item 12) A computer program for causing a computer to function as each of the means of the image processing device according to any one of items 1 to 9.

[0068] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0069] 301: Input section 302: Storage section 303: Adjustment section 304: Conversion section 305: Display section 306: Designation section 307: Determination section 308: Determination section 309: Designation section 310: Judgment section 311: Display section 312: Output section

Claims

1. a determination means for determining whether or not a gradation breakdown occurs as a result of adjusting the color value of the adjustment target lattice point in accordance with the user's operation, based on the lattice point in the lookup table after the adjustment; and an adjustment means for readjusting the adjusted lookup table when it is determined that the gradation breakdown will occur; An image processing device comprising:

2. 2. The image processing apparatus according to claim 1, wherein the determining means determines, as the adjustment target lattice point, a lattice point in the lookup table that is closest to a color value corresponding to the pixel value and that surrounds the color value.

3. 2. The image processing apparatus according to claim 1, wherein the lookup table is a lookup table for converting a color of a first image captured by a first camera into a color of a second image captured by a second camera.

4. 4. The image processing device according to claim 3, wherein the determination means acquires a pixel position designated in response to a user operation on the first captured image after color conversion in which the first captured image is color converted using the lookup table, and sets a lattice point in the lookup table that corresponds to a pixel value of the pixel position of the first captured image as a lattice point to be adjusted.

5. The image processing device according to claim 1, characterized in that the judgment means uses vectors between adjacent lattice points in the adjusted lookup table to judge whether or not a gradation breakdown occurs due to a reversal of the front-to-back relationship of the positions of the lattice points in the adjusted lookup table.

6. 2. The image processing apparatus according to claim 1, wherein said adjustment means adjusts the color values ​​of the adjustment target lattice points so as not to cause a gradation breakdown.

7. 2. The image processing apparatus according to claim 1, wherein the adjustment means displays a result of the adjustment made by the adjustment means on a display screen.

8. 2. The image processing apparatus according to claim 1, wherein the lattice points in the lookup table are lattice points in an L*a*b* color space.

9. moreover, 2. The image processing apparatus according to claim 1, further comprising a display unit for displaying a result of color conversion using the lookup table adjusted by said adjustment unit.

10. moreover, An imaging means; a color conversion means for converting a color of the captured image captured by the imaging means using the lookup table adjusted by the adjustment means; The image processing device according to claim 1 , further comprising:

11. An image processing method performed by an image processing device, comprising: a judgment step in which a judgment means of the image processing device determines, among lattice points in a lookup table for color conversion, a lattice point corresponding to a pixel value at a pixel position designated in response to a user operation as an adjustment target lattice point, and judges whether or not a gradation breakdown occurs as a result of adjusting the color value of the adjustment target lattice point in response to the user operation, based on the lattice point in the lookup table after the adjustment; an adjustment step in which, when it is determined that the gradation breakdown occurs, the adjustment means of the image processing device readjusts the lookup table after the adjustment; An image processing method comprising:

12. A computer program for causing a computer to function as each of the means of the image processing apparatus according to any one of claims 1 to 9.

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