JP4900039B2 - Color adjustment apparatus and program - Google Patents

Description

  The present invention relates to a color adjustment device, a color adjustment method, and a program.

There is a color adjustment function as a function for adjusting a color image. The color adjustment function includes global color adjustment that corrects the color balance, brightness, and the like of the entire color image, and partial color adjustment that corrects a specific region to be adjusted and a specific color. Of these, a typical example of the latter partial color adjustment is a color that is stored by many people as an image of the target color (hereinafter referred to as “memory color”). There is an adjustment to bring it closer.
For example, Patent Document 1 describes a gradation conversion technique that adjusts the appearance of gradation in the details of an image independently of the adjustment of the light / dark balance of the entire image.

JP 2006-114006 A

Here, in general, for partial color adjustment, for example, a setting suitable for a certain color image is suitable for the other image, for example, because it affects the color of an area other than the adjustment area of the image. The setting may not be correct.
An object of the present invention is to perform partial color adjustment suitable for each color image.

According to the first aspect of the present invention, the color point in the predetermined area including the color point to be adjusted in the color image is directed to the color point in the predetermined area including the color point to be adjusted based on the predetermined parameter. A movement processing unit that performs a movement process, the color image in which the color point is moved by the movement processing unit, and the original color image before the color point is moved are compared, and the color image A movement amount calculation unit that calculates a movement amount of the color point in one or a plurality of pixel units, and the movement processing unit includes the one or more pixel units calculated in the movement amount calculation unit. The color adjustment device is characterized in that the parameter is changed based on an integral value over the entire color image or a partial region with respect to the movement amount of the color point .

According to a second aspect of the present invention, in the color adjustment apparatus according to the first aspect, the movement processing unit is a size of a partial color space in which the parameter is an area where the color point is moved in a predetermined color space. It is characterized by setting.
According to a third aspect of the present invention, in the color adjustment apparatus according to the second aspect, the movement processing unit relates to the movement amount of the color point in the partial color space set by the parameter, and the adjustment target. The amount of movement from the color point to the color point to be adjusted is maximized, and the amount of movement of the color point approaches 0 as it approaches the outline of the partial color space.

The invention according to claim 4 is characterized in that the movement processing unit changes the parameter based on the integral value weighted according to the position of the pixel on the color image. The color adjustment device.
The invention according to claim 5 is the color adjustment apparatus according to claim 4 , wherein the movement processing unit changes the parameter so that the integral value approaches a predetermined value.
The invention according to claim 6 is the color adjustment apparatus according to claim 1 , wherein the movement processing unit and the movement amount calculation unit respectively repeat the movement processing and the calculation of the movement amount a plurality of times. is there.

According to a seventh aspect of the invention, the movement processing unit and the movement amount calculation unit reduce the color image, perform the plurality of movement processes on the reduced color image, and calculate the movement amount. 7. The color adjusting apparatus according to claim 6, wherein the color adjusting device is repeated.

According to an eighth aspect of the present invention, a color point in a predetermined area including a color point to be adjusted in a color image is stored in a computer, and a color point in a predetermined area including a color point that is an adjustment target based on a predetermined parameter. Comparing the color image in which the color point is moved with the original color image before the color point is moved, and one or a plurality of pixel units on the color image And the parameter based on an integrated value over the entire color image or a partial area with respect to the calculated movement amount of the color point in one or a plurality of pixel units. The program is characterized by realizing a function of changing the.

In the invention according to claim 9 , when the color point in the predetermined area including the color point to be adjusted is moved toward the color point in the predetermined area including the color point to be adjusted, a predetermined color space is used. 9. The program according to claim 8, wherein the parameter for setting a size of a partial color space which is an area where the color point is moved is used.

  This program may be executed by loading a program stored in a reserved area such as a hard disk or a DVD-ROM into the RAM, for example. In addition, there is a form that is executed by the CPU in a state stored in the ROM in advance. Further, when a rewritable ROM such as an EEPROM is provided, only a program may be provided and installed in the ROM after the apparatus is assembled. In providing this program, it is also conceivable that the program is transmitted to the apparatus via a network such as the Internet and installed in the ROM of the apparatus.

According to the first aspect of the present invention, partial color adjustment suitable for each color image can be performed as compared with the case where the present invention is not adopted.
According to the second aspect of the present invention, compared to the case where the present invention is not adopted, it is possible to reduce the influence of color adjustment in a region other than the color adjustment target region on the color image.
According to the third aspect of the present invention, compared to the case where the present invention is not adopted, the color continuity is maintained at the boundary of the region targeted for color adjustment, and the color changes unnaturally on the color image. This can be suppressed.

According to the first aspect of the present invention, it is possible to grasp the influence of performing color adjustment in a region other than the color adjustment target region on the color image.
According to the fourth aspect of the present invention, it is possible to grasp the influence of performing the color adjustment in the region other than the color adjustment target region on the color image according to the position on the color image.
According to the fifth aspect of the present invention, compared to the case where the present invention is not adopted, it is possible to reduce the influence of performing color adjustment in a region other than the color adjustment target region on the color image.

According to the sixth aspect of the present invention, compared with the case where the present invention is not adopted, the influence of performing the color adjustment in the area other than the color adjustment target area on the color image can be reduced with high accuracy. Can do.
According to the seventh aspect of the present invention, it is possible to shorten the adjustment processing time when performing color adjustment, compared to the case where the present invention is not adopted.

According to the eighth aspect of the present invention, partial color adjustment suitable for each color image can be performed as compared with the case where the present invention is not adopted.
According to the ninth aspect of the present invention, as compared with the case where the present invention is not adopted, it is possible to reduce the influence of performing color adjustment in a region other than the color adjustment target region on the color image.
According to the eighth aspect of the present invention, it is possible to grasp the effect of performing color adjustment in a region other than the color adjustment target region on the color image.

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
[Embodiment 1]
FIG. 1 is a block diagram illustrating an overall configuration of an image processing apparatus 1 including a color adjustment apparatus to which the exemplary embodiment is applied. The image processing apparatus 1 illustrated in FIG. 1 includes an image data input unit 10, a color adjustment device 20 that performs partial color adjustment, and an image data output unit 30. In addition, the color adjustment apparatus 20 according to the present embodiment includes a color space conversion unit 21, a representative color calculation unit 22, a target color calculation unit 23, a partial color space setting unit 24, a color adjustment unit 25, a color difference analysis unit 26, and a color space. A conversion unit 27 is provided.
In the color adjustment apparatus 20, a CPU (not shown) performs a color space conversion unit 21, a representative color calculation unit 22, a target color calculation unit 23, a partial color space setting unit 24, a color adjustment unit 25, a color difference analysis unit 26, and a color space conversion. A program for realizing each function of the unit 27 is read from a main storage unit (not shown) into a RAM or the like in the color adjustment apparatus 20 and various processes are performed.

  The image data input unit 10 is, for example, image data represented by color signals in an sRGB color space, which is a device-dependent color space (device-dependent color space) from a display device such as a liquid crystal display or an image reading device such as a scanner. To get. Then, the acquired image data is sent to the color adjustment device 20.

In the color adjustment device 20, the color space conversion unit 21 acquires image data from the image data input unit 10. Then, the color space conversion unit 21 converts the color signal of the sRGB color space into the color signal of the YCbCr color space, which is a device-independent color space (device-independent color space), for the acquired image data. The converted color signal of the YCbCr color space is sent to the representative color calculation unit 22, the color adjustment unit 25, and the color difference analysis unit 26.
The representative color calculation unit 22 performs a process of extracting a color point (representative color) to be adjusted from the image data. For example, when the image data is based on a person photo image having a person as a subject, the person's skin color is extracted as a representative color to be adjusted.
As a process for extracting the representative color to be adjusted, for example, a method described in Japanese Patent Application Laid-Open No. 2006-155595 can be used. That is, a value representing a ratio between different color components among a plurality of color components representing the colors of the pixels of the color image is obtained as the color component ratio. Then, a color component ratio space that is a space with the color component ratio as an axis is formed, and pixels in a target region are extracted using the color component ratio space. According to this method or the like, the representative color can be automatically extracted. The representative color may be manually extracted by the user using color adjustment software. Note that any method can be used as a method for extracting the representative color to be adjusted, and the method is not limited to the above method.
Then, the representative color calculation unit 22 sends information regarding the color coordinates of the extracted representative color to the partial color space setting unit 24.

The target color calculation unit 23 performs processing for determining a color point (target color) to be an adjustment target.
As a process for determining the target color, for example, a method described in JP-A-2004-254303 can be used. That is, in the color image, the distance between the representative color representing the color that represents the specific area and the target color representing the target color in the specific area in the color space. A certain color adjustment distance is calculated. Then, using the color adjustment distance, the optimum target color representing the color of the specific area after color adjustment is calculated between the representative color and the target color. The target color may be manually set by the user using color adjustment software. Note that any method for determining the target color can be used, and the method is not limited to the above method.
Then, the target color calculation unit 23 sends information regarding the color coordinates of the determined target color to the partial color space setting unit 24.

The partial color space setting unit 24 performs a process of setting a partial color space that is an area for color adjustment in the YCbCr color space and a process of adjusting the size of the partial color space. Specifically, a partial color space including the color coordinates of the representative color extracted by the representative color calculation unit 22 and the color coordinate of the target color determined by the target color calculation unit 23 is a YCbCr color space. Set to. Thereafter, the set size of the partial color space is adjusted as necessary based on the degree of influence E (see later stage) calculated by the color difference analysis unit 26.
First, a method used when setting a partial color space in the partial color space setting unit 24 of the present embodiment will be described, and adjustment of the size of the partial color space will be described later.

The partial color space setting unit 24 sets the partial color space in the YCbCr color space using, for example, the following method described in Japanese Patent Application Laid-Open No. 2004-112694.
FIG. 2 is a diagram illustrating an example of a partial color space set in the YCbCr color space. As shown in FIG. 2, the partial color space setting unit 24 first sets a spherical closed region Q1 having a radius r1 centered on the color coordinate P1 of the representative color extracted by the representative color calculation unit 22, and the target color. A spherical closed region Q2 having a radius r2 around the color coordinate P2 of the target color determined by the calculation unit 23 is set. The radius r1 and the radius r2 here are set in advance as first parameter values used when the partial color space setting unit 24 first sets the partial color space. In the example of FIG. 2, r1 = r2 = r is set, but r1 ≠ r2 may be set.
Further, a cylinder Q3 that is parallel to a straight line connecting the color coordinates P1 and the color coordinates P2 and circumscribes the spherical closed region Q1 and the closed region Q2 (the length of the cylinder Q3 is equal to the length of the line segment P1P2). Set.
Then, with the outer surface of the cylinder Q3 and the outer surfaces of the closed region Q1 and the closed region Q2 as outer shells, a capsule-shaped space surrounded by the outer shell (inside the region indicated by the solid line in FIG. 2) is a partial color space CAP_1. Set as.

Further, the partial color space setting unit 24 may set a partial color space in the YCbCr color space using, for example, a method described in JP-A-2006-135628. In this method, since the sensitivity to changes in brightness (Y) and chromaticity (CbCr) in the human eye is different, the brightness of color coordinates (Y ) Component adjustment and chromaticity (CbCr) component adjustment are set by different conversion functions. For example, for a lightness (Y) component, a predetermined gradation function (gradation curve) is used, and for a chromaticity (CbCr) component, a method described in Japanese Patent Application Laid-Open No. 2004-112694 (see FIG. 4 at a later stage). Is used. In this case, as shown in FIG. 3 (a diagram illustrating another example of the partial color space set in the YCbCr color space), a cross section obtained by cutting the partial color space CAP_1 in FIG. 2 along a plane parallel to the CbCr plane. A substantially cylindrical body having an upper surface H2 and a lower surface H1 having a shape is set as an outline, and a space surrounded by the outline of the substantially cylindrical body (inside an area indicated by a solid line in FIG. 3) is set as a partial color space CAP_2. Hereinafter, the partial color spaces CAP_1 and CAP_2 are also simply referred to as “partial color space CAP”.
Then, the partial color space setting unit 24 sends information regarding the set partial color space CAP to the color adjustment unit 25.
Note that any method can be used as the method of setting the partial color space CAP, and the method is not limited to the above method.

The color adjustment unit 25 performs a process of adjusting the color signal acquired from the color space conversion unit 21 in the partial color space CAP set by the partial color space setting unit 24. Specifically, the color signal is acquired from the color space conversion unit 21, and the movement process related to the color signal (color coordinate) in the partial color space CAP set in the partial color space setting unit 24 in the acquired color signal. That is, color coordinate adjustment processing is performed. As described above, the partial color space setting unit 24 and the color adjustment unit 25 constitute a movement processing unit that performs a color point movement process in the partial color space CAP.
FIG. 4 is a diagram for explaining color coordinate movement processing when the partial color space CAP_1 shown in FIG. 2 is used as an example. First, based on the information about the partial color space CAP acquired from the partial color space setting unit 24, the color signal in the partial color space CAP is extracted from the color signals acquired from the color space conversion unit 21. Then, a movement process is performed in which the color coordinates acquired from the color space conversion unit 21 are moved according to a certain rule in the direction of the color coordinates P2 which is the target color in the partial color space CAP. Here, a vector used when moving the color coordinate in the direction of the color coordinate P2 according to a certain rule is referred to as a “movement vector”. In particular, a movement vector starting from the color coordinate P1 of the representative color in the partial color space CAP and ending at the color coordinate P2 of the target color is set as a reference vector. As shown in FIG. 4, regarding the color coordinate P1 of the representative color, the reference vector is moved to the color coordinate P2 of the target color using the reference vector as a movement vector.

In this case, as a rule used when moving the color coordinate in the direction of the color coordinate P2, the rule is used in a region closer to the outline of the partial color space CAP than the color coordinate P1, which is a representative color in the partial color space CAP. For the color coordinates to be used, a rule is used in which a movement vector having a smaller movement amount is used as it is closer to the outline. Then, in the outline of the partial color space CAP, the movement vector is set so that the color coordinate hardly moves or more preferably does not move at all (the movement amount is “0”).
In order to suppress the occurrence of tone reversal and color reversal, for color coordinate points located on the same movement vector parallel to the reference vector, the movement vector is moved before and after the color coordinates are moved. At the same time, the rule of conversion is used so as not to change the order of the arrangement.

  Next, FIG. 5 is a diagram for explaining color coordinate movement processing when the partial color space CAP_2 shown in FIG. 3 is used as another example. In the movement processing of the color coordinates here, the movement vector component having the same rule as in FIG. 4 is used for the chromaticity (CbCr) component. On the other hand, for the lightness (Y) component, a movement vector component according to a predetermined gradation function (gradation curve) is used. Therefore, as shown in FIG. 5, the chromaticity (CbCr) plane follows the same rules as those shown in FIG. A move process is performed.

Subsequently, the color difference analysis unit 26 is an example of a movement amount calculation unit, and analyzes the color difference between the color signal adjusted by the color adjustment unit 25 and the color signal of the original image acquired from the color space conversion unit 21. Perform the process. Specifically, the difference (color difference: movement amount of the color point in the color space) between the color signal adjusted by the color adjustment unit 25 and the color signal of the original image is calculated for each pixel on the original image. To do. And the color difference pixel value data which makes the calculated color difference for every pixel the pixel value in the pixel are produced | generated, and the integral value of color difference pixel value data is calculated. Further, the influence degree E is obtained based on the integrated value of the color difference pixel value data, and is used as a determination element when the partial color space setting unit 24 adjusts the size of the partial color space CAP. The influence degree E here is a scale indicating the magnitude of the influence on the area other than the adjustment area due to the setting of the partial color space CAP having a predetermined size by the partial color space setting unit 24. The influence of the adjustment process performed by the color adjustment unit 25 on the original image is grasped based on the magnitude of the influence degree E.
Although the color difference is calculated for each pixel on the original image here, the color difference may be calculated using a plurality of pixels as a unit. In that case, for example, a method of calculating an average of the color differences in a plurality of pixels as one unit by calculating a color difference in the plurality of pixels can be used.

FIG. 6 is a diagram for explaining the influence of the adjustment process performed by the color adjustment unit 25 on the original image. FIG. 6 shows, as an example, a case where the skin color is adjusted in a human photograph image taken with a person as a subject, where (a) is an original image, and (b) is an area where calculated color-difference pixel value data exists. It is the figure which piled up (the hatched part in a figure) on the image after adjustment.
In the example illustrated in FIG. 6, the partial color space CAP is set by the partial color space setting unit 24 using the area A in which the skin color of the person who is the subject is expressed as the adjustment area. Therefore, the skin color of the person in the region A is adjusted to the target color point (target color). However, since the colors existing in the partial color space CAP are uniformly color-converted, the regions B, C, and D shown in FIG. 6B, which are color regions close to the human skin color in the YCbCr color space. The color is also converted. As a result, the color difference pixel value data described above is generated in the regions B, C, and D.

Therefore, in the color difference analysis unit 26, in order to measure the influence on the region other than the adjustment region due to the setting of the partial color space CAP by the partial color space setting unit 24, the region (region A and the region where the color difference pixel value data is generated) is measured. An integral value of the color difference pixel value data in the regions B, C, and D) is calculated. Then, the degree of influence E is obtained based on the integral value of the color difference pixel value data, and is used as a determination factor when adjusting the size of the partial color space CAP set by the partial color space setting unit 24.
Specifically, the calculated degree of influence E is sent to the partial color space setting unit 24, and the partial color space setting unit 24, when the sent degree of influence E is larger than, for example, a predetermined value, The size of the partial color space set by the setting unit 24 is adjusted again.
It should be noted that when integrating the color difference pixel value data, a method of limiting the color difference pixel value data, which is a partial area of the color image (region A and regions B, C, D), A method performed over the entire region can be used.

Integrated value D of the color difference pixel value data areas A and B shown in FIG. 6, C, if (i, j) th color difference pixel value of the pixel with p _ij in D, the following equation (1) Can be expressed as The integral value D calculated from the equation (1) may be output as the influence degree E to the partial color space setting unit 24 as it is.
In the following, the vertical coordinate of the image is i, and the horizontal coordinate of the image is j. In the following description, equations (1) to (3) correspond to [Equation 1] to [Equation 3].

Further, the vertical integration of the image in the region A and the regions B, C, and D as shown in FIG. 7 (a diagram for explaining the integration in the vertical direction of the image) is performed. The degree of influence E may be calculated by weighting according to the spread in the horizontal direction on the image.
That is, to calculate the vertical integral value d _j about horizontal j-th chrominance pixel value data of an image in the following equation (2).

For example, a case is assumed where the subject is a person photo image. In this case, there is a premise that the person is generally located in the center of the image, calculate the degree of influence E as impact E of the integrated value d _j of a region close to the opposite ends of the transverse direction of the image is increased To do. For example, a weight w _j having characteristics as shown in FIG. 8 (a diagram showing characteristics of the weight w _j) is prepared for the spread in the horizontal direction (j) on the image. Then, weighting by the weight w _j is performed on the integrated value d _j in the vertical direction (i) calculated by the expression (2). That is, the influence degree E is calculated by the following equation (3). As a result, the spread in the horizontal direction (j) of the image is reflected in the influence degree E for the regions (regions B, C, and D) where the color fluctuates other than the region A that is the adjustment region.

In equation (2), Equation (3) has been calculated integral value d _j in the vertical direction (i), by calculating the integral value d _i in the lateral direction (j), the color is varied region ( For the regions B, C, and D), the influence E may reflect the spread in the vertical direction (i) of the image. In this case, it can be similarly obtained by replacing i and j in the equations (2) and (3). Thus, in this embodiment, the direction of integration may be any direction.

The color difference analysis unit 26 sends the calculated degree of influence E to the partial color space setting unit 24. The partial color space setting unit 24, for example, a radius r1 and a radius r2 (r1 = r2 = r) which are first parameter values for setting the partial color space CAP_1 illustrated in FIG. It is determined whether or not to change.
That is, the size of the partial color space CAP_1 in FIG. 2 is determined by the first parameter value that sets the partial color space CAP_1. If the radius r, which is the first parameter value, is increased, the partial color space CAP_1 can be increased. . If the radius r is reduced, the partial color space CAP_1 can be reduced. Therefore, the partial color space setting unit 24 makes a determination regarding the degree of influence E. For example, when the degree of influence E is larger than a predetermined value, the radius r is decreased to reduce the size of the partial color space CAP_1. The partial color space CAP_1 is reset. For example, when the influence E is small, the radius r is increased, and the partial color space CAP_1 is reset so as to increase the size of the partial color space CAP_1.

FIG. 9 is a diagram showing a general relationship between the size of the partial color space CAP and the degree of influence E. In FIG. As shown in FIG. 9, if the partial color space CAP is set to be large, the influence on other areas other than the adjustment area also becomes large, and the influence degree E increases. Therefore, whether or not to change the first parameter value can be determined by setting a predetermined reference value for the degree of influence E and determining whether the degree of influence E is larger or smaller than the reference value. The reference value of the degree of influence E here may be set, for example, as a level that may seriously affect the image quality when the reference value is exceeded. If the degree of influence E calculated using the partial color space CAP_1 set by the first parameter value (first parameter value) is larger than the reference value provided for the degree of influence E, the first The parameter value is changed to a parameter value (second parameter value) for setting the partial color space CAP having a size smaller than this parameter value.
Specifically, the radius r1 and the radius r2 (r1 = r2 = r) as the first parameter values are changed to the radius r1 ′ and the radius r2 ′ (r1 ′ = r2 ′ <r) as the second parameter values. change. At this time, when the radius r1 and the radius r2 as the first parameter values are set to r1 ≠ r2, the radius r1 ′ (r1 ′ <r1) and the radius r2 ′ as the second parameter values, respectively. Change to (r2 ′ <r2).

On the other hand, if the degree of influence E is smaller than the reference value of the degree of influence E, for example, the parameter value is changed to a parameter value (second parameter value) for setting the partial color space CAP_1 having a size smaller than the first parameter value. May be.
Specifically, the radius r1 and the radius r2 (r1 = r2 = r) as the first parameter values are changed to the radius r1 ′ and the radius r2 ′ (r1 ′ = r2 ′> r) as the second parameter values. change. At this time, when the radius r1 and the radius r2 that are the first parameter values are set to r1 ≠ r2, the radius r1 ′ (r1 ′> r1) and the radius r2 ′ as the second parameter values, respectively. Change to (r2 ′> r2).
In this case, if the degree of influence E is smaller than the reference value, the first color parameter value may not be changed and the partial color space CAP set by the first parameter value may be used as it is.
Even when the partial color space CAP_2 shown in FIG. 3 is used, the adjustment processing of the size of the partial color space CAP_2 is performed in the same manner as described above.

When the partial color space CAP is reset as a result of the determination regarding the degree of influence E, the partial color space setting unit 24 sends information about the reset partial color space CAP to the color adjustment unit 25.
The color adjustment unit 25 adjusts the color signal acquired from the color space conversion unit 21 again in the partial color space CAP reset by the partial color space setting unit 24. Specifically, the color signal is acquired from the color space conversion unit 21, and the color signal (color coordinate) in the partial color space CAP reset by the partial color space setting unit 24 in the acquired color signal is adjusted. Process.
Then, the color signal subjected to the adjustment process again by the color adjustment unit 25 is sent to the color space conversion unit 27 as the color signal of the final adjustment image.
The color space conversion unit 27 converts the YCbCr color space into a color signal in the sRGB color space. Then, the converted color signal of the sRGB color space is sent to the image data output unit 30.

  Further, the color adjustment unit 25 may send the color signal subjected to the adjustment process again in the reset partial color space CAP to the color difference analysis unit 26 and calculate the influence degree E again. Then, the influence degree E calculated by the color difference analysis unit 26 is sent to the partial color space setting unit 24 again. The partial color space setting unit 24 determines whether to change the radius r1 ′ and the radius r2 ′, which are the second parameter values for setting the reset partial color space CAP, based on the sent influence degree E. judge. Thereafter, the same processing as described above is performed. Then, a final adjustment image is determined and sent to the color space conversion unit 27 as a color signal of the determined final adjustment image.

  Here, FIG. 10 is a flowchart illustrating an example of processing relating to color signal conversion performed in the partial color space setting unit 24, the color adjustment unit 25, and the color difference analysis unit 26. As shown in FIG. 10, the partial color space setting unit 24 sets the partial color space CAP using the first parameter value used when the partial color space CAP is first set (S101). Then, the color adjustment unit 25 adjusts the color signal acquired from the color space conversion unit 21 within the partial color space CAP set by the partial color space setting unit 24 (color point movement processing) (S102). The color difference analysis unit 26 is a color difference pixel value in an area where color difference pixel value data that is a color difference between the color signal adjusted by the color adjustment unit 25 and the color signal of the original image acquired from the color space conversion unit 21 is generated. The influence degree E is calculated based on the integrated value of the data (S103). The calculated degree of influence E is sent to the partial color space setting unit 24.

If the sent influence degree E is larger than the reference value (S104), the partial color space setting unit 24 sets a parameter value (second parameter) for setting the partial color space CAP having a size smaller than the first parameter value. Value). Then, the partial color space CAP is reset using the changed parameter value (second parameter value) (S105).
Then, returning to step 102, the color adjustment unit 25 adjusts the color signal acquired from the color space conversion unit 21 again in the partial color space CAP reset by the partial color space setting unit 24. Then, if necessary, the processes of Step 103 to Step 105 are repeated. When the influence degree E finally becomes equal to or less than the reference value (S104), the color signal adjusted by the color adjusting unit 25 is used as the final adjusted image. The color signal is sent to the color space conversion unit 27 (S106).

  In the process of FIG. 10, the color signal adjustment accuracy is increased by repeating the color signal adjustment process a plurality of times while changing the partial color space CAP little by little. However, since the processing time becomes relatively long, the processing in steps 102 to 105 described above may be performed using an image obtained by reducing the original image. If the reduction rate of the original image is such that no loss of image information occurs, the continuity of the image information is not lost. Therefore, when the final adjusted image in step 106 is output, the original image size is returned to the color space. You may output to the conversion part 27. FIG.

FIG. 11 is a diagram illustrating a case where the skin color is adjusted in a person photograph image taken with a person as a subject by the processing illustrated in FIG. 10. FIG. 10A shows an original image. FIG. 10B shows an area after the adjustment of a region (hatched portion in the figure) where color difference pixel value data exists when the color signal is adjusted within the partial color space CAP set by the first first parameter value. FIG. FIG. 10C shows the color difference pixel value data when the color signal is adjusted in the partial color space CAP in which the influence E is finally equal to or less than the reference value by repeating the processing of step 102 to step 105. FIG. 6 is a diagram in which a region where there is (a hatched portion in the drawing) is superimposed on an image after readjustment.
As shown in FIG. 11, in the color adjustment apparatus 20 according to the present embodiment, the parameter value for setting the partial color space CAP is adjusted to reset the size of the partial color space CAP. The influence on the area is reduced (see FIG. 10C).

  As described above, in the color adjustment apparatus 20 according to the present embodiment, when color adjustment is performed while moving only in the partial color space CAP including the representative color and the target color, The color from the color point to be adjusted (representative color) to the color point to be adjusted (target color) while setting the size of the partial color space CAP suitable for the image to be reduced and reducing the influence on the entire image Adjustments can be made.

1 is a block diagram illustrating an overall configuration of an image processing apparatus including a color adjustment apparatus to which the exemplary embodiment is applied. It is a figure explaining an example of the partial color space set to YCbCr color space. It is a figure explaining the other example of the partial color space set to YCbCr color space. It is a figure explaining the adjustment process of the color coordinate in the case of using the partial color space shown in FIG. It is a figure explaining the movement process of the color coordinate in the case of using the partial color space shown in FIG. It is a figure explaining the influence which the adjustment process performed in the color adjustment part gave to the original image. It is a figure explaining the integration of the vertical direction of a picture. Is a diagram showing characteristics of the weighting w _j. It is the figure which showed the general relationship between the magnitude | size of a partial color space, and an influence degree. It is the flowchart which showed an example of the process regarding the conversion of the color signal performed in a partial color space setting part, a color adjustment part, and a color difference analysis part. It is the figure which showed the case where skin color is adjusted in a person photograph image by the process shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Image processing apparatus, 10 ... Image data input part, 20 ... Color adjustment apparatus, 21, 27 ... Color space conversion part, 22 ... Representative color calculation part, 23 ... Target color calculation part, 24 ... Partial color space setting part, 25 ... Color adjustment unit, 26 ... Color difference analysis unit, 30 ... Image data output unit

Claims (9)

A movement processing unit configured to move a color point in a predetermined area including a color point to be adjusted in a color image toward a color point in the predetermined area including a color point to be adjusted based on a predetermined parameter;
The color image in which the color point has been moved by the movement processing unit is compared with the original color image before the color point is moved, and the color image is obtained in units of one or more pixels on the color image. A movement amount calculation unit for calculating the movement amount of the color point,
The movement processing unit is configured to calculate the parameter based on an integral value over the entire color image or a partial area related to the movement amount of the color point in the unit of one or a plurality of pixels calculated by the movement amount calculation unit. A color adjusting device characterized by changing.   The color adjustment apparatus according to claim 1, wherein the movement processing unit sets a size of a partial color space in which the parameter is an area where the color point is moved in a predetermined color space.   The movement processing unit is configured to maximize the movement amount from the color point to be adjusted to the color point to be adjusted with respect to the movement amount of the color point in the partial color space set by the parameter. 3. The color adjusting apparatus according to claim 2, wherein the amount of movement of the color point approaches 0 as it approaches the outline of the partial color space. The movement processing unit, based on the integral values weighted according to the position of the pixel on the color image, the color adjustment device according to claim 1, wherein changing the parameter. The color adjustment apparatus according to claim 4 , wherein the movement processing unit changes the parameter so that the integral value approaches a predetermined value.   The color adjustment apparatus according to claim 1, wherein the movement processing unit and the movement amount calculation unit each repeat the movement processing and the movement amount calculation a plurality of times. The movement processing unit and the movement amount calculation unit reduce the color image, and repeat the plurality of movement processes and the calculation of the movement amount for the reduced color image. Item 7. The color adjusting apparatus according to Item 6 . On the computer,
A function of moving a color point in a predetermined area including a color point to be adjusted in a color image toward a color point in a predetermined area including a color point to be adjusted based on a predetermined parameter;
The color image in which the color point has been moved is compared with the original color image before the color point is moved, and the amount of movement of the color point in units of one or more pixels on the color image A function for calculating
A program for realizing a function of changing the parameter based on an integral value over the entire color image or a partial area relating to the calculated movement amount of the color point in the unit of one or a plurality of pixels. . When moving a color point in a predetermined area including the color point to be adjusted toward a color point in the predetermined area including the color point to be adjusted, the color point is moved in a predetermined color space. 9. The program according to claim 8, wherein the parameter for setting a size of a partial color space which is an area to be used is used.

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