JP4164334B2 - Image processing apparatus and method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a technique for performing color conversion to output an input color image signal.
[0002]
[Prior art]
Conventional methods for converting an input color image signal to an image signal in an output device are divided according to the characteristics of the output image. For example, photographic toning correction that preferably outputs an image image, text or graph image, etc. Graphics color correction and the like that preferably output business documents are known. In particular, in recent presentation materials and the like in which graphics color correction is used, a gradation pattern in which the color or brightness changes gradually from one color to another tends to be frequently used as the background of an image or the texture of a figure.
[0003]
Regarding colors used for such gradations, white (W) -primary colors (Red, Green, Blue, Cyan, Magenta, Yellow ( Yellow))-black (Bk) gradation is often used. In general, since gradation reproduction with vivid colors is preferred, the color at the outermost edge of the color gamut of the output device is used for color reproduction between white (W), primary color, and black (Bk). Is done. At this time, in the color reproduction of the primary color between white (W) -primary color-black (Bk), an appropriate color is selected so that gradation is not reduced or vividness is not lost depending on the set brightness. Color correction processing using a lightness tolerance range is performed so as to obtain a point.
[0004]
For example, according to Japanese Patent Laid-Open No. 2000-287096, when a monitor color space as an input color space and an output color space in a color printer are compressed, the color displayed on the monitor is lightness (L), saturation (C ), Converted to the hue (H) three-color space, and after compressing the monitor brightness to the printer brightness range, each hue was mapped to the point where the color difference is minimized in the LC space and compressed. . In addition, the compression is performed by mapping to a point where the color difference is minimum in the LC space above the reference lightness, and the compression is performed while maintaining the lightness below the reference lightness. That is, the mapping point and the mapping point brightness are defined based on the condition that the color difference is minimum and the single condition that is limited to the brightness, that is, maintaining the brightness.
[0005]
Further, according to Japanese Patent Laid-Open No. 2001-203906, when the monitor color space as the input color space and the output color space in the color printer are compressed, the brightness of the mapping color in the output color space is determined by the hue of the color in the input color space. The lightness of the cusp color in the input color space mapped to the surface of the gamut of the receiving device that matches the lightness of the mapping point obtained by mapping the lightness axis of the input color space and the lightness axis of the output color space, It is determined by weighting by the ratio of the saturation of the color of the input color space and the highest saturation of the colors having the hue and lightness of the color of the input color space in the output color space. Thus, the brightness of the mapping point is uniquely determined based on the relationship between the input color space and the output color space.
[0006]
[Problems to be solved by the invention]
However, the L * a * b * color space and the LCH color space described above do not necessarily match human visual characteristics, and even colors that are on the same hue angle cannot be seen as the same hue due to differences in brightness. There is a problem that even if the color is on the same hue angle, it cannot be seen as the same hue due to the difference in saturation. Therefore, in a color correction result using the same hue angle in the L * a * b * color space or the LCH color space, an input color image signal is converted into an image signal in the output device, and an arbitrary image output by the output device is converted. When the mapping brightness is adjusted with respect to the colors, particularly the primary color, there is a problem that the target hue does not have the same color. Furthermore, if only the lightness condition based on the input color space is controlled, the difference in the three-dimensional shape of the input color space and the output color space cannot be considered. As a result, the degree of degradation and the poor gradation characteristics were caused.
[0007]
The present invention has been made in view of the above-described conventional example, and maps a predetermined color signal within the hue range determined based on the equi-hue line information for human vision, the condition for brightness, and the condition for saturation. The object is to realize color reproduction that optimizes the color and the entire mapping result by performing color conversion with a chromaticity point set.
[0008]
[Means for Solving the Problems]
  In order to achieve the above object, the image processing apparatus of the present invention comprises the following arrangement. That is,
  An image processing apparatus that converts a color signal of an input image signal into a color signal of an output image,
  In an output device that outputs the output imagecolorColor gamut information storage means for storing color gamut information indicating a reproduction color gamut;
  The lightness divided for the color gamut information indicating the color gamut in the output device is set, the equi-hue line is obtained for each lightness, and the equi-hue line for each lightness and the color gamut in the output device Determining means for determining gradation point information that is an intersection with the outline of
  The gradation point on the white point side and the black point side as viewed from the point of the maximum saturation, which satisfies the saturation condition and the lightness condition predetermined for the maximum saturation for the predetermined hue in the color gamut information. Acquire each lightness of information, and lightness tolerance range according to each lightness of the gradation point information on the white point side and black point sideCalculating means for calculating
  Calculated by the calculating meansMapping of the input image signal of the predetermined hue within the lightness tolerance rangeAnd color conversion means for performing the above.
  In order to achieve the above object, the image processing apparatus of the present invention includes the following steps. That is,
  Color gamut information storage means for storing color gamut information indicating a color reproduction color gamut in an output device that outputs an output image;Convert the color signal of the input image signal to the color signal of the output imageOf image processing equipmentAn image processing method comprising:
  The lightness divided for the color gamut information indicating the color gamut in the output device is set, the equi-hue line is obtained for each lightness, and the equi-hue line for each lightness and the color gamut in the output device A determination step of determining gradation point information that is an intersection with the outline of
  The gradation point on the white point side and the black point side as viewed from the point of the maximum saturation, which satisfies the saturation condition and the lightness condition predetermined for the maximum saturation for the predetermined hue in the color gamut information. A calculation step of obtaining each lightness of the information and calculating a lightness tolerance range according to each lightness of the gradation point information on the white point side and the black point side;
  A color conversion step of mapping the input image signal of the predetermined hue within the lightness tolerance range calculated in the calculation step;It is characterized by having.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Before describing a preferred embodiment of the present invention in detail with reference to the accompanying drawings, an outline of the first embodiment of the present application will be described. When converting a color signal of an input image into an output color signal, For the shape of the output color space, the target hue for the primary color is determined in advance as equi-hue line information that has the same hue for human vision, and the equi-hue information is used for the output color space. After determining the mapping target data, the brightness range to be mapped in the output color space is determined in advance in the mapping target data based on the condition for brightness and the condition for saturation, and the mapping brightness point is determined within the determined range. Make a decision. In other words, for the shape of the output color space, the color that has the mapping chromaticity point of the primary color set within the lightness range determined based on the information on equi-hue lines for human vision and the conditions for lightness and saturation An object of the present invention is to perform color conversion processing that realizes color reproduction that optimizes the color of the primary color and the entire mapping result by performing conversion.
[0010]
In the color conversion for converting the input color signal to the output color signal, the target hue for the primary color is previously determined as equal hue line information that is the same hue for human vision with respect to the shape of the output color space. After the output color space is determined as the mapping target data using the equal hue information, the mapping target data becomes the mapping target in the output color space based on the condition for lightness and the condition for saturation. An object of the present invention is to provide a user interface and a lightness tolerance range in which a lightness range is determined in advance and a mapping lightness point can be determined within the determined range.
[0011]
Furthermore, by using the lightness tolerance range, it is possible to calculate and provide a lightness tolerance evaluation value of the set mapped lightness point.
[0012]
This will be described in detail below.
[0013]
FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to Embodiment 1 of the present invention.
[0014]
In FIG. 1, reference numeral 101 denotes a CPU, which includes a RAM 103 and an operation unit according to data and control programs stored in the ROM 102, an OS (operating system), an application program (hereinafter simply referred to as an application), a color matching processing module, a device driver, and the like. 104, various controls of the image processing unit 105, the monitor 106, the input device 107, and the output device 108 are performed. An input device 107 includes an image reading device such as an image scanner including a CCD sensor and a color measurement device, and inputs color space information data for which a profile is to be created. An output device 108 includes, for example, an ink jet printer, a thermal transfer printer, a dot printer, and the like, and prints and outputs a color image. The RAM 103 provides a work area when executing various control programs, and is also used as a temporary save area for data input from the input device 107 or the operation unit 104. The operation unit 104 includes a keyboard and a mouse, and is used for setting the output device 108 and inputting various data. An image processing unit 105 performs image processing including setting of lightness range information according to the present embodiment and profile creation by color gamut mapping processing using the set lightness range information. Reference numeral 106 denotes a monitor (display unit) that displays a result processed by the image processing unit 105, data input by the operation unit 104, and the like.
[0015]
FIG. 2 is a block diagram showing a configuration of the image processing unit 105 shown in FIG. Here, a configuration for mapping input information having the color space of the input image to the color space of the output image will be described.
[0016]
Reference numeral 201 denotes a profile creation unit 201. Reference numerals 209, 210, and 211 denote input terminals. Information regarding the color gamut of the printer that is the output device 108 is input from the input terminal 209, and input color space information that is information regarding the color gamut of the input device 107 is input from the input terminal 210. Is entered. An input color gamut storage unit 204 stores input color space information input from the input terminal 210. Reference numeral 205 denotes a printer color gamut storage unit that stores color gamut information of the printer that is the output device 108 and is input from the input terminal 209. A mapping parameter calculation unit 206 includes a gradation point information setting unit 213 and a lightness range setting unit 214, which will be described later. The printer color gamut information stored in the printer color gamut storage unit 205, and the input color With reference to the input color space information stored in the gamut storage unit 204, a color space compression parameter required by the gamut mapping unit 207 described later is calculated.
[0017]
The color gamut mapping unit 207 refers to the input color space information and the printer color gamut information, refers to the color space compression parameter so that the input information can be reproduced with an image quality having a desired gradation, Maps the color gamut of the input color space to the printer color gamut. Hereinafter, this mapping result is referred to as a mapping color reproduction range.
[0018]
Reference numeral 208 denotes a profile creation unit, which has a correspondence relationship between the input color space and the mapped color reproduction area, input color information (RGB data) for outputting a predetermined color in the input color space, and a printer serving as the output device 108. With reference to printer output color information (CMYK data) for outputting the colors, a profile for conversion from input data to printer output color information is created. The created conversion profile is written into the RAM 202. In the mapping operation of the profile creation unit 208 in the first embodiment, the L * a * b * color space is used as the uniform color system.
[0019]
In addition, RGB image data is input from the input terminal 211 and supplied to the interpolation unit 203. The interpolation unit 203 refers to the conversion profile stored in the RAM 202, converts the RGB image data into printer output color information, and passes the printer output color information to the output device 108 through the output terminal 212.
[0020]
Here, as described above, the mapping parameter calculation unit 206 acquires, as part of its function, a gradation point information setting unit 213 that acquires gradation point information for calculating a color space compression parameter from the output color reproduction range. And a brightness range setting unit 214. Here, the lightness range setting unit 214 maps the optimum color over the output color reproduction range based on the gradation point information obtained by the gradation point information setting unit 213 for the primary color (RGB) of the input RGB image data. The brightness range for each hue for determining the brightness range is determined. Further, the color gamut mapping unit 207 sets a primary color mapping point within the brightness range set by the brightness range setting unit 214. Further, other mapping parameters (tone point information) are set.
[0021]
Next, the operation of the mapping parameter calculation unit 206 according to the first embodiment will be described with reference to the flowchart of FIG.
[0022]
FIG. 3 is a flowchart for explaining the operation of the mapping parameter calculation unit 206 according to the first embodiment.
[0023]
First, in step S1, the input color space color gamut information and the printer color gamut information are stored in the input color gamut storage unit 204 and the printer color gamut storage unit 205 of the profile creation unit 201. In step S2, the target hue value is determined for the designated color. In step S3, brightness values divided for the printer color gamut are set, and equal hue lines having target hue values in each brightness range are obtained as values on the uniform color system. Here, in the uniform color system, the coordinates of the intersection between the constant hue line for each lightness and the contour of the printer color reproduction area are obtained from the contour information for the printer color reproduction area and the uniform hue line information for each lightness. Hereinafter, the intersection coordinates for each brightness are referred to as gradation point information.
[0024]
In step S4, uniform color system coordinate information that is maximum saturation is set based on the gradation point information (intersection coordinates) obtained in step S3. In step S5, a saturation condition that is a ratio condition set in advance with respect to the maximum saturation value is acquired based on the uniform color system coordinate information of the maximum saturation obtained in step S4. Next, the process proceeds to step S6, on the basis of the gradation point information obtained in step S3, the white point side as viewed from the maximum saturation point that satisfies the saturation condition that is a ratio set in advance with respect to the maximum saturation value. The target brightness (white point brightness information, black point brightness information) of the tone point information on the black point side is acquired, and this is defined as the brightness range A.
[0025]
Next, the process proceeds to step S7, and based on the maximum saturation point information obtained in step S4, the lightness information and white point lightness information of the maximum saturation point, and the lightness information and black point lightness information of the maximum saturation point. To obtain a brightness condition with a preset ratio. Next, proceeding to step S8, the lightness information of the maximum saturation point obtained in step S4, the lightness information of the maximum saturation point acquired in step S7, the whiteness lightness information, the lightness information of the maximum saturation point, and the black point lightness. Based on the tone point information obtained in step S3 using the brightness conditions set for each information, the target brightness of the tone point information on the white point side and the black point side viewed from the maximum saturation point is determined. And this is defined as the brightness range B.
[0026]
In this way, it progresses to step S9 and acquires the common brightness area | region of the brightness range A calculated | required by step S6, and the brightness range B calculated | required by step S8. In step S10, the common brightness area acquired in step S9 is defined as the brightness tolerance range of the primary color mapping target point in the hue set in step S2. In step S11, the color gamut mapping unit 207 uniquely sets the primary color mapping point in the hue set in step S2 from the gradation point information within the lightness tolerance range defined in step S10. Next, proceeding to step S12, the primary color mapping point set at step S11 is stored in the RAM 202. Then, the process proceeds to step S13, and it is determined whether or not the above processing has been performed for all hues to be processed. If there is still an unprocessed one, the process returns to step S2, the remaining hue value to be processed is set, and the above process is repeated. In this manner, when all the colors to be processed in step S13 are processed, the process proceeds to step S14, where the color gamut mapping unit 207 determines the primary color mapping point for each hue determined according to the above-described processing, and After other gradation points are set in sequence, a profile for converting from the input color space to the printer color reproduction gamut is created by mapping processing according to the procedure according to the flowchart of FIG.
[0027]
FIG. 4 is a flowchart for explaining mapping processing in the color gamut mapping unit 207 according to the first embodiment. In this embodiment, a continuous locus connecting a certain color is called a gradation line.
[0028]
First, in step S21, a sample point for defining a color gamut mapping is determined. This sample point is divided into a surface sample point that defines the mapping of the surface of the color gamut of the input information and an internal sample point that defines the mapping of the color gamut of the input information. Next, in step S22, it is determined where the surface sample point should be mapped in the printer color reproduction range. Note that the mapping result of the surface sample point is not necessarily located on the surface of the printer color reproduction range. In step S23, it is determined where the internal sample point should be mapped in the printer color gamut. However, in this case, the mapping is controlled so that the mapping result of the internal sample point is always located within the printer color reproduction range.
[0029]
Subsequently, the process proceeds to step S24, in which a gradation line connecting two different surface sample points (hereinafter referred to as a surface gradation line) is defined. In step S25, it is determined where the surface gradation line should be mapped in the printer color gamut. The mapping result of the surface gradation line is not necessarily located on the surface of the printer color reproduction area. In step S26, a gradation line connecting two different internal sample points (hereinafter referred to as an internal gradation line) is defined. In step S27, it is determined where in the printer color reproduction area this internal gradation line should be mapped. The mapping is controlled so that the mapping result of the internal gradation line is always located inside the printer color reproduction range. Finally, the process proceeds to step S28, and the mapping result from the input color space color gamut to the mapping color gamut is obtained from the surface tone line and the internal tone line for the color desired to represent the mapped color gamut. To do.
[0030]
As described above, according to the first embodiment, for each specified hue value, the gradation point information that defines the lightness range for reproducing the optimum lightness of the primary color is acquired and stored, Based on the stored brightness range, a mapping point for mapping the sample point in the input color space can be determined, and a profile for performing color gamut mapping processing can be created based on the mapping point. Using this profile, smooth gradation reproduction can be realized for each of the designated hue values.
[0031]
Next, the image processing method according to the first embodiment will be described in detail. Here, the input color space information is RGB color space, and the distribution of the surface sample points in the RGB color space will be described by taking the red surface as an example.
[0032]
FIG. 5 is a diagram for explaining the relationship between saturation and lightness in red (R). Here, the color reproduction range in the RGB color space is three points of white (Red) and black (Black). It represents with the cutting plane cut | disconnected by the plane which passes through.
[0033]
Point 501 indicates white (255, 255, 255), and point 502 indicates black (0, 0, 0). The vertical axis represents the brightness axis that changes from (0, 0, 0) to (255, 255, 255) in the (R, G, B) coordinates. Ri represents the surface sample point on the red surface, and the index i is assigned in order of increasing brightness. Here, R6 is the primary color (R) with the highest saturation and is a sample point corresponding to this red.
[0034]
It should be noted that such sample points are similarly set for each of the green, blue, cyan, magenta, and yellow surfaces.
[0035]
In the following, the process for performing the optimum mapping brightness of red will be described, but it goes without saying that it can be similarly applied to other colors, that is, green, blue, cyan, magenta, and yellow.
[0036]
FIG. 6 is a block diagram showing a functional configuration of the gradation point information setting unit 213 of the mapping parameter calculation unit 206 according to the first embodiment, and FIG. 7 is a flowchart for explaining the processing.
[0037]
Reference numeral 601 denotes an input color space memory which stores input color space information supplied from the input color gamut storage unit 204. An output color space information memory 602 stores the printer color space information supplied from the printer color gamut storage unit 205 as color space coordinate information of a uniform color. Reference numeral 603 denotes an HVC color space reference data memory which stores HVC color space reference data for conversion into coordinate values of the uniform color space of the printer color space information. A hue data memory 604 stores hue information to be reproduced for a specified color. A lightness division information memory 605 stores lightness information for obtaining gradation point information for the output color space. Reference numeral 606 denotes an equi-hue line setting unit, which is a lightness specified by the lightness division information stored in the lightness division information memory 605, and sets a constant hue line based on the specified hue information. An outline calculation processing unit 607 obtains outline coordinate information of the output color space from the output color space information stored in the output color space information memory 602. An intersection calculation processing unit 608 obtains an intersection between the outer coordinate information and the equi-hue line coordinates for each brightness. Reference numeral 609 denotes an equi-hue line data memory for storing equi-hue line data. A gradation point data memory 610 stores coordinate information of intersection points between outline coordinate information and equal hue line coordinates for each brightness.
[0038]
Next, the operation of the gradation point information setting unit 213 will be described with reference to the flowchart of FIG.
[0039]
First, in step S31, input color space information and output color space information are acquired and stored in the input color space memory 601 and the output color space information memory 602, respectively. Here, the input color space information is RGB data, and the output color space information is printer color gamut information described by L * a * b * data. In step S32, the target hue value of the designated color is acquired.
[0040]
In this case, red (R) is designated in the RGB data shown in FIG. 5, and a hue value for reproducing red with a preferable color in the printer color reproduction area is obtained as a target hue value. This target hue value is a hue value in the HVC color space in which lightness, hue, and saturation change are equal to the human eye. In the present embodiment, it is assumed that an optimal hue value is defined for a primary color such as a primary color in advance.
[0041]
FIG. 8 is a diagram showing a data configuration example of the hue data memory 604, and here, a target hue value as a target in the HVC color space is set.
[0042]
In memory areas 1201 to 1206 for storing hue information for each color, the target hue values of red, green, blue, cyan, magenta, and yellow are stored in advance for each sample point. Each target hue value is indicated by a hue H in the Munsell color space. Therefore, in the present embodiment, the Munsell hue value “5R”, which is the red target hue value, is read from the memory area 1201 and set as the target hue value.
[0043]
In the present embodiment, the Munsell color space is used as the HVC space for obtaining equal hue lines for each lightness, and this Munsell color space and the L * a * b * color are stored in the HVC color space reference data memory 603. Information for associating coordinate points with the space is stored. Then, equi-hue line data for each lightness is set based on the target hue value and lightness division information.
[0044]
The hue data memory 604 has a configuration in which a target hue value can be designated and registered for a sample point sampled by the user in the color designated by the user or in the gamut mapping unit 207. Also good. In FIG. 8, reference numerals 1207 and 1208 denote memory areas in which the user can register arbitrary hue values. As described above, the hue value of the color designated by the user is registered as the corresponding hue value for the sample point designated by the user, and when obtaining the mapping point of the sample point designated by the user, the W-designation is performed. It is possible to perform mapping so as to have smooth gradation characteristics between the color and Bk.
[0045]
In step S33, the lightness division number n in the output color space is acquired. Here, the lightness division information between W-color-Bk is determined in advance for the printer color reproduction range which is the output color space. In the present embodiment, the division number n and the lightness information L * = L1 to Ln for the lightness are stored in the divided lightness information memory 605. Therefore, in step S33, they are stored in the divided lightness information memory 605. It is only necessary to read the brightness division number n.
[0046]
In step S34, a division number counter for setting equal hue line information is set. Here, the lightness division number n acquired in step S33 is stored in a division number counter (not shown) of the equi-hue line setting unit 606. In step S35, one piece of lightness information stored in the divided lightness information memory 605 is selected based on the lightness division information stored in the division number counter, and is set as a constant hue line setting target lightness.
[0047]
Next, in step S36, equi-hue line information for obtaining a coordinate point for realizing a target hue value in the outline of the printer color reproduction area is set. This is because the equal hue line setting unit 606 realizes the target hue value at the equal hue line setting target brightness on the HVC color space with respect to the equal hue line setting target brightness selected in step S35, and changes in the saturation direction. The equal hue line information is obtained as an HVC color space coordinate value with reference to the HVC color space reference data. At this time, the equi-hue line information may be information on continuous coordinate points (line segments) or some discrete coordinate point information. In the present embodiment, the latter form (discrete) has equi-hue line information. The HVC color space coordinate value, which is information on the equal hue line obtained in this way, is converted into L * a * b * data by the equal hue line setting unit 606 and stored in the equal hue line data memory 609.
[0048]
FIG. 9 is a diagram illustrating an example of the equi-hue line data memory 609 set in the present embodiment.
[0049]
In the figure, each of the memories 1401, 1409, and 1410 is a set of L * a * b * coordinate data representing the equal hue line setting brightness, L * = L1, L2, and Ln. The indexes indicated by reference numerals 1402 to 1408 are obtained by assigning numbers in ascending order of saturation with respect to the equal hue lines when obtaining the equal hue lines. Each is stored.
[0050]
In step S37, the intersection calculation processing unit 608 determines printer color gamut information in order to obtain a coordinate point that realizes a target hue outside the printer color gamut with the brightness that is the target of setting the equi-hue line. And the intersection coordinates of the contour of the printer color reproduction area and the equal hue line are calculated based on the equal hue line information for the equal hue line setting target brightness obtained in step S36.
[0051]
In step S38, the coordinates of the intersection point between the contour of the printer color reproduction area and the equi-hue line at the target brightness are obtained, and the value n of the division number counter is decreased by one. In step S39, it is checked whether or not the division number counter value n is “0”. If it is “0”, the process proceeds to step S40, and the printer color gamut of all the target lightness values for setting the equi-hue lines is obtained. Since the intersection coordinates defining all the target hue values in the outline are calculated, all the calculated intersection coordinates are stored in the gradation point data memory 610, and this process is terminated. If it is not “0”, the process proceeds to step S35, and the brightness information stored in the split brightness information memory 605 is selected based on the split counter value n, and the above-described processing is executed.
[0052]
FIG. 10 is a diagram illustrating a data configuration example of the equi-hue line data memory 1301 for red in the gradation point data memory 610 that stores all the calculated intersection coordinates.
[0053]
In FIG. 10, for each specified color, the intersection coordinates of the outline of the printer color reproduction area and the equi-hue line are stored for each divided lightness. The equi-hue line data memory 1301 stores red sample points R1 to R11 shown in FIG. 5 and mapping point coordinates in the L * a * b * space at the W and Bk points.
[0054]
FIG. 11 is a diagram for explaining a result based on the processing according to the present embodiment.
[0055]
In the figure, the vertical axis represents the lightness axis L *, and the plane coordinate axes represent the orthogonal coordinate axes a * axis and b * axis in the L * a * b * uniform color system, respectively. Reference numeral 1100 denotes a printer color reproduction range. Between W-Bk, each of the lightness L1 to Ln corresponds to the divided lightness information in the above processing. Also, corresponding hue information L1 to Ln, the equi-hue line information for reproducing the Munsell hue “5R” is indicated by a dotted line.
[0056]
The outline of WR-Bk in the printer color reproduction area 1100 in FIG. 11 and the intersection point based on the equi-hue line information indicated by the dotted line are indicated by black circles. In this figure, it is shown as a sectional view of a region surrounded by the outline of WR-Bk and the gray line of W-Bk. The black circles on the outline of WR-Bk from W to Bk are the actual coordinates of the intersection points, and were obtained based on the HVC space that has uniform brightness, hue, and saturation change for the human eye. It is a chromaticity point. Therefore, a change in hue with respect to lightness indicated by a black circle causes a smooth change in hue for human vision between WR and Bk.
[0057]
FIG. 12 is a block diagram illustrating the configuration of the brightness range setting unit 214 of the mapping parameter calculation unit 206 according to the present embodiment.
[0058]
A gradation point data memory 610 for storing coordinate information of intersection points of outline coordinate information and equi-hue line coordinates for each lightness, which are gradation points at a specified hue and lightness in the output color space; A maximum saturation processing unit 801 for acquiring maximum gradation point data in a hue specified from point data, a lightness range condition data memory 802 storing saturation and lightness conditions for obtaining a lightness range, and a lightness range A lightness range condition processing unit 803 that sets a lightness tolerance range based on the conditions stored in the condition data memory 802 and a lightness tolerance range data memory 804 that stores the set lightness tolerance range data are provided.
[0059]
Next, the operation of the brightness range setting unit 214 will be described with reference to the flowchart of FIG.
[0060]
First, in step S51, the coordinate information of the intersection between the outline coordinate information stored in the gradation point data memory 610 and the equi-hue line coordinates for each brightness is acquired. In step S52, the gradation point data for the designated hue stored in the gradation point data memory 610 is acquired. As shown in FIG. 10, the gradation point data is the outermost point coordinate data group on the color reproduction range having a specified hue for a predetermined brightness from the white point to the black point. Here, the R data shown in FIG. 5 is the designated hue, and tone point information that reproduces the hue that performs the preferred color reproduction in red is selected as shown in FIG. 11 in the printer color reproduction range. To be acquired.
[0061]
Next, the process proceeds to step S53, and tone point data having the maximum saturation is calculated from the tone point data between WR and Bk acquired in step S52. Here, the gradation data having the maximum saturation point is obtained by calculating the saturation with the gradation point coordinates for each discrete brightness, which is the original data, and determining the gradation point data having the maximum saturation. Also good. Alternatively, gradation point data for continuous intermediate lightness is calculated by interpolation processing from the gradation point coordinates for each discrete lightness which is the original data, and the maximum saturation is determined from the individual saturation information, and the level based on the result is calculated. The coordinate coordinate data may be used. The former case can be applied if the number of discrete brightness data of the original data is sufficient.
[0062]
FIG. 14 is a diagram for explaining a method for obtaining the lightness range A from the saturation condition for the maximum saturation.
[0063]
In FIG. 14, the gradation point data in the specified hue acquired in step S52 is schematically shown with the saturation C on the horizontal axis and the lightness L * on the vertical axis. In the figure, 1701 indicates the white point coordinates, 1702 indicates the black point coordinates, and 1703 indicates the maximum saturation point Rd in the gradation point data. Reference numeral 1704 denotes the saturation Cr at the maximum saturation point Rd. Here, as indicated by reference numeral 1705 with respect to the maximum saturation Cr, the gradation point data at the position where the saturation is decreased by the saturation width ΔCr from the maximum saturation point Rd is viewed from the maximum saturation point Rd. The target gradation point Lcup 1706 on the white point side and the target gradation point Lclo 1707 on the black point side as viewed from the maximum saturation point Rd. Further, the saturation condition acquired after step S54 is a condition for the ratio of the saturation width ΔCr to the maximum saturation Cr of the maximum saturation point Rd.
[0064]
Here, the brightness range condition data memory 802 stores the ratio of the maximum saturation point Rd to the saturation Cr as shown by 1501 to 1508 for each hue, as shown in FIG. Yes. In these 1501 to 1506, conditions for determining the brightness range of the six primary colors RGBCMY are stored in advance, and these are hue data set by the user and an area for storing the set brightness target. It is. When the designated hue is red, the white side saturation condition (W-Col) Ctrw and the black side saturation condition (Col-Bk) Ctrk are set as the saturation conditions shown in FIG. , Acquired from the brightness range condition data memory 802.
[0065]
The relationship of the saturation width ΔCr with respect to the white side saturation condition Ctrw, the black side saturation condition Ctrk, the maximum saturation Cr, and the maximum saturation Cr is expressed by the following equations (1) and (2). Coordinate points satisfying the relationship of these equations (1) and (2) are estimated from the gradation point data, and the coordinate points of the target gradation point Lcup on the white point side and the target gradation point Lclo on the black point side are determined respectively. .
[0066]
White side ΔCr = Ctrw × Cr (1)
Black side ΔCr = Ctrk × Cr (2)
In step S54, the white side saturation condition Ctrw for the saturation Cr of the maximum saturation point Rd is acquired from the brightness range condition data memory 802 as a condition for calculating the lightness tolerance range. Next, the process proceeds to step S55, and the target gradation point Lcup on the white point side is obtained according to the equation (1) using the white side saturation condition Ctrw acquired in step S54. Next, the process proceeds to step S56, and the brightness at the target gradation point Lcup on the white point side that satisfies the saturation condition obtained in step S55 is defined as the brightness upper limit value A1.
[0067]
In step S57, the black side saturation condition Ctrk for the saturation Cr of the maximum saturation point Rd is acquired from the brightness range condition data memory 802 as a condition for calculating the lightness tolerance range. Next, the process proceeds to step S58, and the target gradation point Lclo on the black point side is obtained according to the equation (2) using the black side saturation condition Ctrk obtained in step S57. Then, the process proceeds to step S59, and the lightness at the target tone point Lclo on the black point side that satisfies the saturation condition obtained in step S58 is defined as the lightness lower limit value A2. Thus, in step S60, the brightness range A is defined based on the brightness upper limit A1 and brightness lower limit A2 using the saturation condition for the maximum saturation point Rd obtained in steps S56 and S59.
[0068]
FIG. 16 is a diagram for explaining a method for obtaining the lightness range B from the lightness condition for the maximum saturation point Rd.
[0069]
In FIG. 16, with respect to the maximum saturation point Rd, the brightness difference value between the brightness at the maximum saturation point Rd and the brightness of the white point 1701 is ΔLw 1708, and the brightness difference between the brightness of the maximum saturation point and the brightness of the black point 1702 Let the value be ΔLk1709. Then, the gradation point data corresponding to the lightness at a position where the lightness is shifted by the lightness width ΔLrw1710 from the maximum saturation point Rd to the white point side is Llup 1712, and the lightness is the lightness width ΔLrk1711 from the maximum saturation point Rd to the black point side. The gradation point data corresponding to the lightness at the position shifted from is set to Lllo1713.
[0070]
Further, the brightness conditions acquired in step S61 and after are the conditions for the ratio of ΔLrw to the brightness width ΔLw and the ratio of ΔLrk to the brightness width ΔLk.
[0071]
In the lightness range condition data memory 802, as shown in FIG. 15, as lightness conditions, the lightness difference between the maximum saturation point and the white point (ΔLw) and the lightness difference between the maximum saturation point and the black point (ΔLk). The ratios (W-Col, Col-Bk) to are stored as indicated by 1501-1508 for each hue. Here, after step S61, when the designated hue is red, after step S54, the white color saturation condition Ltrw and the black color saturation condition Ltrk as the saturation condition shown in FIG. Obtained from data memory 802.
[0072]
Here, the relationship between the white side lightness condition Ltrw, the black side saturation condition Ltrk, the maximum saturation point Rd and ΔLrw with respect to the lightness width ΔLw at the white point, and the maximum saturation point Rd and ΔLrk with respect to the lightness width ΔLk at the black point are: It is shown by the following formulas (3) and (4). Coordinate points satisfying the relationship of these equations (3) and (4) are estimated from the gradation point data, and are determined as the coordinate points of the target gradation point Llup on the white point side and the target gradation point Lllo on the black point side, respectively. The
[0073]
White side ΔLrw = Ltrw × ΔLw Equation (3)
Black side ΔLrk = Ltrk × ΔLk Equation (4)
In step S61, a lightness interval value ΔLw defined by the lightness at the maximum saturation point Rd and the lightness of the white point is obtained. Next, the process proceeds to step S62. As conditions for calculating the lightness tolerance range, the lightness at the maximum saturation point Rd and the white side lightness condition Ltrw with respect to the lightness interval value ΔLw defined by the white point lightness are used as the lightness range condition data. Obtained from memory 802. Next, the process proceeds to step S63, and the target gradation point Llup on the white point side is obtained according to the equation (3) using the white side lightness condition Ltrw obtained in step S62. Next, the process proceeds to step S64, and the brightness at the target gradation point Llup on the white point side that satisfies the brightness condition obtained in step S63 is defined as the brightness upper limit value B1.
[0074]
In step S65, a lightness interval value ΔLw defined by the lightness at the maximum saturation point Rd and the lightness of the white point is obtained. Next, the process proceeds to step S66, where the white side lightness condition Ltrk for the lightness interval value ΔLk defined by the lightness at the maximum saturation point Rd and the lightness at the black point is used as the condition for calculating the lightness tolerance range. Obtained from the memory 802. Next, the process proceeds to step S67, and the target gradation point Lllo on the black point side is obtained according to the equation (4) using the black side lightness condition Ltrk acquired in step S66. In step S68, the lightness at the target tone point Lllo on the black point side that satisfies the lightness condition obtained in step S67 is defined as the lightness upper limit B2. Thus, in step S69, the lightness range B is determined by the lightness upper limit B1 and the lightness lower limit B2 using the lightness condition for the maximum saturation point Rd obtained in step S64 and step S68.
[0075]
Next, proceeding to step S70, the common range of the lightness range A obtained at step S60 and the lightness range B obtained at step S69 is obtained.
[0076]
FIG. 17 is a diagram illustrating an example of the relationship between the lightness range A1801 and the lightness range B1802.
[0077]
Here, the lightness region where the lightness range A and the lightness range B overlap is the lightness region Ltr1803 indicated by the lightness upper limit Lt1 = Llup and the lightness lower limit Lt2 = Lllo. In the first embodiment, the lightness region Ltr common to the lightness range A and the lightness range B is set as the lightness tolerance range.
[0078]
Next, proceeding to step S71, the lightness range common to the lightness range A and the lightness range B obtained at step S70 is defined as the lightness allowable range at the primary color mapping point of the red hue in the present embodiment, and this is defined as the lightness range. It is stored in the allowable range data memory 804.
[0079]
Next, the process proceeds to step S72, where it is determined whether or not this lightness tolerance range has been obtained for all the hues specified in step S51. If not, the process returns to step S52, and the unprocessed hues are determined. The processes from step S52 to step S72 are repeated. On the other hand, if it is determined in step S72 that the process for obtaining the lightness tolerance range has been performed for all hues, the process shown in this flowchart is terminated.
[0080]
FIG. 18 is a diagram illustrating an example of a lightness tolerance range data memory 804 that stores all of the lightness tolerance range data. Here, the lightness tolerance range data calculated according to the flowchart of FIG. 13 is stored for each hue as indicated by 1601 to 1608. Each of these items 1601 to 1606 represents lightness tolerance range data of six colors of RGBCMY as primary colors. These store brightness tolerance range data of hue data arbitrarily set by the user.
[0081]
Next, the configuration of the color gamut mapping unit 207 for obtaining a mapping point for a sample point from the gradation point and the brightness range stored by the gradation point information setting unit 213 and the brightness range setting unit 214 will be described.
[0082]
FIG. 19 is a block diagram illustrating a configuration of the color gamut mapping unit 207.
[0083]
Reference numeral 1001 denotes a sample point information memory which stores surface sample point information which is RGB data among white, red and black. Reference numeral 1002 denotes a line information memory. Based on the color information held by the sample point information, the tone point of the corresponding hue is obtained from the equi-hue line data memory 609 (FIG. 6) that stores the previously obtained tone point coordinate information. Store information. Reference numeral 1003 denotes a condition information memory which stores a condition element for mapping a target sample point to a printer color reproduction area. Reference numeral 1004 denotes an output data memory which stores mapping point data. Reference numeral 1005 denotes a search processing unit that acquires mapping point data by using the interpolation processing in the interpolation processing unit 1006 for the corresponding mapping point data. The interpolation processing unit 1006 reads the mapping condition corresponding to the target sample point from the condition information memory 1003, and for the discrete gradation point data acquired from the line information memory 1002, the corresponding mapping point data is obtained. To perform interpolation processing. The lightness tolerance range data memory 804 stores lightness range data for primary color mapping.
[0084]
FIG. 20 and FIG. 21 are flowcharts for explaining the operation in the color gamut mapping unit 207 for obtaining the mapping point for the sample point from the gradation point and the brightness range stored in the gradation point information setting unit 213 and the brightness range setting unit 214. It is.
[0085]
First, processing for determining a primary color mapping point will be described with reference to the flowchart of FIG.
[0086]
First, in step S81, sample point information of RGB data between WR-Bk (white-red-black) in the input color space is acquired. In step S82, tone point information of L * a * b * data between white, red and black obtained from the output color space is obtained. In step S83, a control element or control condition for mapping the sample point based on the gradation point on the output color space is acquired. These control elements or control conditions are determined by the color gamut mapping unit 207.
[0087]
In the first embodiment, from the mapping parameter and the printer color gamut information, the brightness when mapping each sample point for RGB data to the printer color gamut is determined when mapping the sample point. In this case, the corresponding brightness in the printer color gamut of each sample point is a control element. This control element may be an element that handles gradation control as a result, such as saturation, distance between mapping points, and ratio of distance between mapping points.
[0088]
In step S84, a target sample point is selected. In step S85, it is determined whether the target sample point selected in step S84 is a primary color target sample point. If the selected target sample point is a primary color target sample point, the process proceeds to step S88, and a mapping point is determined by primary color mapping coordinate point processing described later.
[0089]
On the other hand, if it is determined in step S85 that the sample point is not the primary color target, the process proceeds to step S86, and a mapping point for the sample point is determined based on the control element acquired in step S83. Here, the mapping point coordinates corresponding to the lightness are determined from the gradation point data based on the lightness at the target sample point. Next, the process proceeds to step S87, where it is determined whether the mapping points for all target sample points have been determined. If the mapping points for all target sample points have not been determined, the process returns to step S84, and the remaining sample points are set. Determine the corresponding mapping point. In this way, when the determination of the mapping points to all the target sample points is completed in step S87, this process is terminated.
[0090]
FIG. 21 is a flowchart for explaining the process of determining the mapping point for the primary color target sample point in step S88 of FIG.
[0091]
First, in step S91, the sample point information determined as the primary color target sample point between W and Bk in step S88 of FIG. 20 is acquired. In step S92, a lightness tolerance range that is a control element of the mapping point for the primary color sample point between W-color-Bk is acquired. Next, proceeding to step S93, as shown in FIG. 22, the target lightness of the primary color mapping point is set within the lightness tolerance range. The setting of the target lightness may be arbitrarily determined by the user, or may be appropriately determined by adjusting the mapping lightness within the lightness range based on a preset evaluation value of the mapping result. It may be.
[0092]
In FIG. 22, the acquired lightness tolerance range Ltr1901, the maximum saturation point lightness Lrc1902, and the mapping point target lightness Lrp1903 are shown. Here, when the mapping point target lightness Lrp is set to be brighter than the lightness Lrc of the maximum saturation point, the maximum saturation point with respect to the lightness difference Th1904 between the maximum lightness point lightness Lrc and the lightness tolerance upper limit lightness Lt1. The mapping point brightness is determined so that the mapping point brightness Lrp is set so that the ratio of the brightness difference Pl between the brightness Lrc and the mapping target brightness Lrp becomes a predefined value.
[0093]
Next, proceeding to step S94, based on the gradation point data acquired in step S82 of FIG. 20, based on the target brightness of the mapping point set in step S93 and the brightness information of the gradation point data, the mapping point The coordinate points in the uniform color system are obtained by interpolation. At this time, various interpolation methods such as linear interpolation and nonlinear interpolation may be used. Further, the interpolation processing unit 1006 can execute several interpolation processes, and based on the intersection coordinate information stored in the line information, the degree of linearity in the series of gradation points between W-color (red) -Bk. Accordingly, interpolation may be performed by selecting an appropriate interpolation processing method.
[0094]
In step S95, the coordinate point information of the mapping point obtained by interpolation is determined as the primary color mapping point coordinates in step S94, and a primary color mapping point as shown in FIG. 23 is obtained and stored in the output data memory 1004. Store.
[0095]
By obtaining the optimal mapping point based on the shape of the output color reproduction range for the primary color of RGB data among white, red, and black by the processing according to the flowcharts shown in FIGS. 20 and 21 described above. And an optimum mapping point can be determined within the lightness tolerance range.
[0096]
The processing for determining the mapping point on the printer color gamut shown in the flowcharts of FIGS. 7 and 13 has been described above. Here, it is possible to obtain an optimal primary color mapping point based on the shape of the output color reproduction range for at least the primary colors green, blue, cyan, magenta, and yellow.
[0097]
Thereafter, the image processing unit 105 similarly performs color correction processing on the color gamut information of the output printer with respect to other color data based on the mapping point of the primary color determined within the lightness tolerance range. Through such color correction processing, the color creation color profile is created by the profile creation unit 208.
[0098]
As described above, according to the first embodiment, image data having RGB color space information can be output to a printer using the created profile. In this case, the lightness tolerance range of the primary color map optimized for the shape of the output color space range is acquired, and at least the primary color R, G, B, and C, M, Y mapping points have the lightness. Determined within the allowable range. Therefore, when an image is output from the output device 108 such as a printer, it is possible to reproduce an optimal image with good color reproducibility and no distortion in gradation.
[0099]
[Embodiment 2]
FIG. 24 is a diagram for explaining the second embodiment of the present invention.
[0100]
In FIG. 24, when obtaining the maximum saturation point data Rc 2201 from the gradation point data, white point coordinates 2202, black point coordinates 2203, and coordinate plane origin (achromatic color axis) 2204 are used as origin information for calculating saturation. May be selected, and one point may be selected when calculating the saturation of the gradation point data.
[0101]
Further, in order to select the white point side gradation point, the saturation Cw is referred with the white point 2202 as the origin, and on the other hand, in order to select the black point side gradation point, the saturation Ck is referred with the black point 2203 as the origin. For example, the origin may be appropriately switched from the choices of the origin.
[0102]
[Embodiment 3]
FIG. 25 is a block diagram showing the configuration of the profile creation processing unit according to the third embodiment of the present invention. The parts common to those in FIG.
[0103]
The mapping parameter calculation unit 206 refers to the printer color gamut information, the input color space information, and the color correction information input via the terminal 213 by the user operation and stored in the color correction value storage unit 408. A color space compression parameter necessary for the processing of the area mapping unit 207 is calculated.
[0104]
The operation of the profile creation unit 201 having such a configuration will be described. In the mapping operation of the profile creation unit 201 according to the third embodiment, the L * a * b * color space is used as the uniform color system.
[0105]
First, in response to a command from the CPU 101, the color gamut information of the input color space and the color gamut information of the printer are transmitted. The transmitted two color gamut information is respectively stored in the input color space color gamut storage unit 204 and the printer color gamut storage unit 205 of the profile creation unit 201 as input color space color gamut information and printer color gamut information, respectively. Is done.
[0106]
Next, various parameters necessary for color space compression by the gamut mapping unit 207 are calculated by the operation of the mapping parameter calculation unit 206. When this parameter calculation process is completed, the color gamut mapping unit 207 operates to map the color gamut of the input color space to the printer color reproduction gamut in the uniform color system of the L * a * b * color space. The color gamut mapping unit 207 according to the third embodiment performs a mapping operation according to the flowchart of FIG. 26, and this operation will be described in detail later. Next, the profile creation unit 209 creates a profile for conversion from the input information to the printer color information with reference to the mapping color reproduction range that is the final mapping result, and writes the profile to the RAM 202. When RGB image data is input from the input terminal 211 to the interpolation unit 203, the profile stored in the RAM 202 is referred to convert the RGB image data into output element data, and the converted result is the output terminal 212. To the output device 108.
[0107]
The mapping processing operation in the color gamut mapping unit 207 according to the third embodiment is the same as the processing shown in FIG.
[0108]
FIG. 26 is a flowchart for explaining the operation of the mapping parameter calculation unit 206 according to the third embodiment. Portions common with FIG. 3 are denoted by the same symbols, and the description thereof is omitted. The difference from the flowchart of FIG. 3 described above is that a process (step S110) for evaluating the mapping point is provided between step S11 and step S12.
[0109]
FIG. 27 is a block diagram illustrating a functional configuration of the image processing unit 105 according to the third embodiment of the present invention.
[0110]
In the figure, reference numeral 501 denotes an evaluation target color data storage unit, which stores coordinate values in a uniform color space that measure the color to be evaluated input from the input terminal 510. The evaluation target color data storage unit 501 may store coordinate values in the uniform color space from the colorimeter as the input device 107 via the host computer, or may be calculated by the operation unit 104 or the image processing unit 105. The coordinate value input by doing so may be stored. Further, in this evaluation target color data storage unit 501, color attribute information about what kind of color the evaluation target color is evaluated is stored in association with the evaluation target color. A lightness evaluation unit 502 evaluates lightness at the evaluation target color coordinates. The lightness evaluation unit 502 refers to the printer color gamut information stored in the printer color gamut storage unit 205 and obtains reference lightness and lightness allowable range coordinate information for the lightness of the evaluation target color to obtain reference / lightness allowable range coordinate data. Store in the memory 504. The result and evaluation value evaluated by the lightness evaluation unit 502 are stored in the evaluation result storage unit 505 in association with the evaluation target color. Further, the reference lightness and lightness tolerance area coordinate information stored in the reference / lightness tolerance area coordinate data memory 504 and the evaluation value stored in the evaluation result storage section 503 are displayed on a monitor which is the display section 106. Further, the image processing unit 105 includes the following configuration as a color correction unit using the brightness evaluation result.
[0111]
The display unit 106 displays the reference lightness, the lightness tolerance range coordinate information, and the evaluation value in the evaluation target color that is also the color correction target color. Based on this, the user determines a color correction amount for the color correction target color within the lightness tolerance range, and inputs it through the U / I 506 using the operation unit 104. The color correction amount information input by the user in this manner is stored in the color correction value storage unit 408. When a profile creation instruction for performing color correction processing is given, the profile creation unit 208 having the configuration shown in FIG. 25 creates a profile with reference to the color correction values stored in the color correction value storage unit 408, and outputs the profile. Output through the terminal 511.
[0112]
The configuration example of the lightness evaluation unit 502 is the same as the block diagram showing the functional configuration of the gradation point information setting unit 213 (FIG. 6) according to Embodiment 1 described above, and a description thereof will be omitted. With such a configuration, outline information at a specified hue value is obtained from output color space information for obtaining a lightness tolerance range. Since the process of the brightness evaluation unit 502 is also the same as that in FIG. 7, the description thereof is omitted.
[0113]
Evaluation target information corresponding to human visual characteristics and considering the color gamut in the output device 108 is obtained by the processing according to the flowcharts of FIGS. 7 and 13 described above. In each hue, the maximum saturation coordinate set in step S53 is set as the reference brightness coordinate, and the brightness tolerance range data set in step S71 is stored in the reference / brightness tolerance area coordinate data memory 504 of the image processing unit 105. Store each one.
[0114]
FIG. 28 is a diagram for explaining a data configuration example of the reference / brightness tolerance area coordinate data memory 504.
[0115]
2801 stores the L * a * b * coordinate value of the evaluation target color, and 2802 stores the L * a * b * coordinate value of the maximum saturation color coordinate of the evaluation target color. Further, 2803 stores the L * a * b * coordinate value in the upper-limit brightness tolerance range for the evaluation target color, and 2804 stores the L * a * b * coordinate value in the lower-limit brightness tolerance range for the evaluation target color. Is done. As described above, in the reference / brightness tolerance area coordinate data memory 504, memory areas are set for the color attributes of the evaluation target colors.
[0116]
FIG. 29 is a diagram illustrating an example of a data configuration in the evaluation result storage unit 503 that stores evaluation values and evaluation results according to the third embodiment.
[0117]
An area 2901 is a memory area for storing a color reproducibility evaluation result for the evaluation target color (R). Similarly, the area 2902 stores the color reproducibility evaluation result for the evaluation target color (G), and the area 2903 stores the color reproducibility evaluation result for the evaluation target color (B). In this way, the evaluation result of the color reproducibility for each evaluation target color is stored. The evaluation result includes the color attribute (color) of the evaluation target color, the allowable range position result (evaluation allowable range), the evaluation value, the reference point L * a * b * coordinates, and the evaluation target color L * a * b * coordinates. Are stored.
[0118]
FIG. 30 is a flowchart illustrating processing in which the brightness evaluation unit 502 according to the third embodiment determines the position of the brightness allowable range of the brightness of the evaluation target color.
[0119]
First, in step S <b> 101, the lightness in the evaluation target color is acquired from the reference / lightness tolerance area coordinate data memory 504. In step S102, the evaluation reference color brightness for the evaluation target color is acquired from the reference / lightness tolerance area coordinate data memory 504. In step S 103, the upper and lower brightness values of the lightness tolerance area are read from the reference / lightness tolerance area coordinate data memory 504. In step S104, the lightness in the evaluation reference color and the upper limit lightness in the lightness tolerance range, or the lower limit lightness in the lightness tolerance range are compared, and an allowable range where the lightness in the target color is sandwiched with respect to the evaluation reference lightness is determined. It is determined whether the target color is located on the upper limit side of the lightness tolerance range or the lower limit side of the brightness tolerance range. In this determination, if it is determined that the evaluation target color exists within the evaluation standard lightness and the upper limit lightness of the allowable range, the process proceeds to step S105, and evaluation is performed using the lightness difference between the evaluation standard lightness and the allowable upper limit lightness. Evaluate the target color.
[0120]
On the other hand, if it is determined that the evaluation target color exists at the lower limit lightness of the allowable range, the process proceeds to step S106, and the evaluation target color is evaluated using the lightness difference between the evaluation reference lightness and the allowable range lower limit lightness.
[0121]
When step S105 or S106 is executed in this way, the process proceeds to step S107, and the allowable range position determination result using the selected allowable range and the evaluation value of the evaluation target color with respect to the calculated brightness reference color are stored in the evaluation result storage unit 503. . In step S108, the permissible range position determination result for each evaluation target color stored in the evaluation result storage unit 503 and the evaluation value of the evaluation target color for the lightness reference color are displayed on the display unit 106.
[0122]
Here, in the color reproducibility evaluation according to the third embodiment, the color attribute information specified by the user in advance for the color attribute information, so that the color attribute information can be subjected to lightness evaluation regarding an arbitrary color, The target hue value in the data format of the hue information in the HVC color space in the color information designated in advance by the user is stored in the memory areas 1207 and 1208 shown in FIG. Further, the saturation condition and the lightness condition for obtaining the lightness tolerance range are stored in the memory areas 1507 and 1508 of the lightness range condition data memory 802 shown in FIG.
[0123]
Further, in the third embodiment, the color information specified by the user in advance and the hue of the HVC color space in the color information specified in advance by the user so that the user can perform the brightness evaluation regarding an arbitrary color. A color evaluation value setting unit that can register or add a target hue value according to the data format of information and a saturation condition and a lightness condition for obtaining a lightness tolerance range in a memory may be provided.
[0124]
Next, processing for performing color correction processing using the evaluation value, the evaluation reference color, and the lightness tolerance range for the color correction target color obtained by the above processing will be described.
[0125]
FIG. 31 shows the evaluation value and the color correction possible area on the display unit 106 so that the user can specify the color correction amount in the color correction processing, and the color correction amount is input by U / I. It is a figure which shows an example of this U / I screen. In the figure, the target colors for color correction are divided into RGB, CMY, and other tools, and the user wants to perform color correction by selecting a desired page on the display unit 106 using this U / I. Display U / I. In FIG. 31, RGB color correction is selected.
[0126]
In FIG. 31, reference numeral 3101 denotes a U / I for inputting a color correction amount relating to RGB brightness. The evaluation value of the color correction target color stored in the evaluation result storage unit 503 is displayed as an R evaluation value 3113, a G evaluation value 3125, and a B evaluation value 3137 based on the color attribute information. The lightness in the L * a * b * space for the set evaluation color is displayed as lightness 3112 for R, lightness 3124 for G, and lightness 3136 for B. The bar display corresponding to RGB in this U / I indicates information necessary for each color correction of the corresponding RGB, and at the same time, using each of the pointers 3103, 3115, 3127 movable by the user, each color correction value is used as position information. Visual correction is possible.
[0127]
Next, determination of the color correction value by the R color correction bar will be described.
[0128]
RGB color correction bars are provided corresponding to the respective colors. The left end of each bar indicates the white point brightness of the highest brightness device in the color space of the output device 108, and the right end indicates the color space of the output device 108. The device black point brightness with the lowest brightness is shown. From the left end to the right end of these bars, the lightness distribution of the device white point W and the device black point Bk in the L * a * b * space is arranged side by side. The current brightness of the evaluation color R is indicated by a pointer 3103. This pointer 3103 is also used as a color correction pointer. Further, the lightness in the maximum saturation chromaticity point L * a * b * space in a predetermined hue of the color correction target color stored in the evaluation reference / lightness tolerance coordinate data memory 504 is a pointer 3102 as the evaluation reference lightness in color correction. Indicated by.
[0129]
The lightness tolerance range for the color correction target color stored in the reference / allowable coordinate data memory 504 is A for the whiteness side of the output device 108 with respect to the lightness of the evaluation reference color, and the black point side of the device 108. The allowable range is set as B, and is displayed as a color correctable region 3104 on the bar. In the brightness between the device white point W and the device black Bk, the areas 3105 and 3106 that are not the color correctable area 3104 are displayed as different colors from the color correctable area 3104 as non-color correctable areas. In the correction value determination process using the color correction pointer 3103, the color correction pointer 3103 cannot be moved to the color correction impossible areas 3105 and 3106.
[0130]
Next, determination of a color correction value using each pointer of the R bar, the color correctable area 3104, and the color uncorrectable areas 3105 and 3106 will be described.
[0131]
The R color correction pointer 3103 can be moved left and right on the bar by the user operating the operation unit 104. Accordingly, the user refers to the position of the current color correction target color on the bar, the position of the evaluation reference that is the maximum saturation point, and the color correctable area 3104, and is positioned at an arbitrary position in the color correctable area 3104. The color correction value can be determined by moving the color correction pointer 3103. Furthermore, in the third embodiment, when determining a color correction value, it is also possible to determine the color correction value based on an evaluation value or a numerical value using lightness in the L * a * b * space.
[0132]
Next, color correction determination processing using this evaluation value will be described.
[0133]
In the area 3108, “−1.0” is displayed as the evaluation value in the allowable range on the device white point W side. In 3110, “+1.0” is displayed as the evaluation value in the allowable range on the device black point side. These evaluation values are added with a plus sign and a minus sign so that when the user inputs the evaluation value to the area 3109 for desired color correction, it can be determined to which side the recommended target value is to be moved. Because.
[0134]
In the initial state before the user determines a color correction value, the current evaluation value for the evaluation target color is displayed in the input / display area 3109. The user determines a color correction value by inputting an evaluation value for color correction in this area 3109 as a numerical value. Here, in order to match the recommended target value, “0” may be input. Here, even when numerical values are input to the areas 3108, 3109, and 3110 and the color correction value is determined, when the color correction value is input to the area 3109, the color correction pointer 3103 on the bar described above is input. The color correction can be specified by moving in conjunction with the color correction value.
[0135]
In addition, by operating the movement operation setting buttons 3107 and 3111 on the left and right of these areas 3108 and 3110, the numerical value of the area 3109 and the color correction pointer 3103 on the bar can be moved.
[0136]
Further, when the user designates the pointer 3103 indicating the position of the evaluation reference color indicated by the bar, the corresponding evaluation value can be displayed in the area 3109. Further, even if the user designates an arbitrary position on the color correctable area 3104 on the bar, similarly, the corresponding evaluation value is displayed in the area 3109, and the color correction pointer 3103 is interlocked with the corresponding position on the bar. Moving.
[0137]
Here, by enabling one of the display switching buttons 3138 and 3139, the numerical value to be displayed in the areas 3108, 3109 and 3110 is selected as either the evaluation value or the hue angle value in the L * a * b * space. can do.
[0138]
Next, color correction determination processing using brightness values in the L * a * b * space will be described.
[0139]
In an area 3108, the brightness in the allowable range on the device white point W side is displayed. In the area 3110, the brightness in the allowable range on the device black point Bk side is displayed. In the initial state before the user determines the color correction value, the area 3109 displays the brightness at that time in the evaluation target color. The user can determine the color correction value by inputting the brightness value in this area 3109 as a numerical value for desired color correction. Here, also when the color correction value is determined by inputting a numerical value to the display areas 3108, 3109, and 3110, the color correction pointer 3103 is moved and displayed in conjunction with the input color correction value. When brightness is selected as the color correction value, an evaluation value corresponding to the brightness specified by the user is calculated, and the evaluation value is displayed below the area 3109 although it is not displayed in FIG. There may be.
[0140]
The U / I for determining the R color correction value has been described above, but the operation and display of the U / I for determining the G and B color correction values are the same and will be described briefly.
[0141]
In the case of the evaluation color G, the current brightness of the evaluation color, the G color correction pointer 3115, the pointer 3114 indicating the brightness as the evaluation reference color in the color correction, and the color correction on the device white point side with respect to the brightness of the reference color An allowable area of the target color is C, and an allowable area on the device black point side is D, and a color correctable area 3116 and color uncorrectable areas 3117 and 3118 are shown. Areas 3120 and 3122 for inputting / displaying an allowable range for determining a color correction value numerically, areas 3121 for inputting / displaying a desired color correction value, moving operation setting buttons 3119 and 3123, and display switching buttons 3140 and 3141 are provided. It has been.
[0142]
In the case of the evaluation color B, the current brightness of the evaluation color, the B color correction pointer 3127, the pointer 3126 indicating the brightness that is the evaluation reference color in the color correction, and the allowable range on the device white point W side with respect to the brightness of the reference color , E, and the allowable range on the device black point Bk side is F, and a color correctable region 3128 and color uncorrectable regions 3129 and 3130 are shown. An area 3132, 3134 for inputting / displaying an allowable range for determining a color correction value as a numerical value, an area 3133 for inputting / displaying a desired color correction value, a movement operation setting button 3131, 3135, and a display unit switching button 3142, 3143 is there.
[0143]
When all the RGB color correction values are determined in this way, the OK button 3144 is designated, and the RGB color correction values are stored in the color correction value storage unit 408. When the cancel button 3145 is pressed, the RGB color correction values are initial values, which are restored to the evaluation value data of the evaluation target color, stored in the color correction value storage unit 408, and the U / I 3101 is closed.
[0144]
FIG. 32 is a diagram illustrating a data configuration example of the color correction value storage unit 408 that stores the color correction value determined in this way.
[0145]
A memory area 3201 is a memory area for storing a red color correction value that is a color correction target color. The color correction value includes a color attribute (color) of the evaluation target color, a correction area indicating which side is corrected with respect to the reference color lightness in the lightness tolerance range, and an evaluation value (correction evaluation value) for color correction. , And L * a * b * coordinates after color correction calculated based on the color correction lightness are stored.
[0146]
Each of the memory areas 3202 to 3207 is a memory area for storing color correction values of the color correction target colors having green, blue, cyan, magenta, yellow, which are color correction target colors, and an arbitrary hue specified by the user.
[0147]
In the color correction processing according to the third embodiment, the colors to be subjected to color correction are at least the primary colors red, green, blue, cyan, magenta, and yellow. The CMY color correction value is determined by the CMY color U / I in FIG. 31 (“CMY color” in FIG. 31). Of course, this correction processing may be performed for intermediate colors in intermediate saturation other than the primary color. Therefore, U / for performing color correction processing on a color correction target color having an arbitrary hue specified by the user. Using I (“Other” in FIG. 31), the user may register the color correction target color and determine the color correction value.
[0148]
When performing color correction using the U / I shown in FIG. 31, a window 3301 showing the mapping result as shown in FIG. 33 may be displayed.
[0149]
FIG. 33 is a diagram illustrating a display example of a window that displays the mapping result.
[0150]
In the figure, reference numeral 3310 denotes a button for closing the window 3301. Reference numeral 3302 denotes a display area for displaying the result of color correction. The horizontal axis represents saturation and the vertical axis represents lightness, and represents a cross section of an arbitrary hue in this color space. A color space section 3303 shows all color space sections of the output color space, and a color space section 3304 shows a color space based on the mapping result based on the color correction value. In addition, color correction coordinate values 3305 and 3306 by the U / I color correction pointer shown in FIG. The hue displayed here is not shown in the figure, but can be switched according to the user's designation. Further, regarding the display method, there may be a function of selecting, for example, 3D display in addition to cross-sectional display by hue.
[0151]
Further, the display area 3307 displays the volume of the output color space (original color space). The display area 3308 displays a volume (mapped color space) in the color space based on the mapping result based on the color correction value. In a display area 3309, the ratio of the color space volume of the mapping result by color correction to the volume of the output color space is displayed.
[0152]
Each display in this figure displays the color correction result in real time corresponding to the color correction using U / I shown in FIG. 31, and the user can adjust the brightness by referring to the mapping result. It is possible to determine an optimum color correction value within an allowable range.
[0153]
Further, when performing color correction using the U / I shown in FIG. 31, an automatic color correction value determining U / I for selecting a mapping purpose as shown in FIG. 34 may be used.
[0154]
FIG. 34 is a diagram showing a display example of a window 3401 for the user to set mapping conditions.
[0155]
Reference numeral 3409 denotes a button for closing the U / I 3401. In a color space in which the horizontal axis indicates saturation and the vertical axis indicates lightness, selection buttons 3402 to 3404 that can be selected by the user are displayed for mapping conditions for determining color correction values. When the selection button 3402 is checked, the color correction value within the lightness tolerance range in the U / I shown in FIG. 31 is automatically determined so as to obtain a mapping result that can make maximum use of the output color space. When the selection button 3403 is checked, the brightness reference color that is the maximum saturation color in each hue is determined as the color correction value. When the selection button 3404 is checked, a mapping result that minimizes the total color difference with respect to the target coordinate value of the color conversion result for the input data stored in the color correction value storage unit 408 is obtained. The color correction value within the lightness tolerance range of U / I shown in FIG. 31 is determined.
[0156]
In addition to the target coordinate value of the color conversion result for the input data stored in the color correction value storage unit 408, the target L * a * b * of the color conversion result for the input RGB data as shown in FIG. Alternatively, the user may prepare a file storing the coordinate values, and the file input setting unit 3405 may set the file storing the target coordinate values of the color conversion results for the input data. Further, by using the default setting button 3406, it is possible to return to the target coordinate value data of the color conversion result for the input data stored in advance in the color correction value storage unit 408.
[0157]
After selecting the mapping purpose using the above selection buttons, when a creation button 3408 is designated, a color within the lightness tolerance range in U / I shown in FIG. 31 is obtained so that a mapping result for realizing the mapping purpose is obtained. A correction value is determined.
[0158]
FIG. 36 is a diagram illustrating an example of a U / I that allows a user to arbitrarily set a hue with respect to color attribute information. Note that this UI may have a function that allows the hue value to be changed for the memory area of the hue data memory 604 shown in FIG. 8 and the memory area of the gradation point data memory 610 shown in FIG.
[0159]
In the figure, 3601 is a U / I for changing the set hue value of RGB. A case where the hue value is set will be described. Here, when the setting of the hue value of red is changed, the L * a * b * coordinate designating portion is used as an input display area 3602 for inputting an L value, an input display area 3603 for inputting an a * value, and a b * value. There is an input display area 3604 for input. For the L * a * b * values input in the input display areas 3602 to 3604, a selection button 3607 for acquiring the HVC hue value of each L * a * b * value and selecting whether to set these, or One of the selection buttons 3606 for selecting whether to acquire the tone point of the hue hue in the L * a * b * color space is selected. In the hue value input display area 3605, a hue value in the HVC color space or the L * a * b * color space can be input using the selection buttons 3606 and 3607.
[0160]
When the HVC space is selected here, the value set by the user is set in the memory area of the hue data memory 604 shown in FIG. On the other hand, when the hue value (Lch) in the L * a * b * color space is selected, the gradation point data corresponding to the designated hue value is calculated, and the memory of the gradation point data memory 610 shown in FIG. Set to area. A default setting button 3608 can return the input setting value to the setting value.
[0161]
In addition, a file storing gradation point data arbitrarily determined by the user as shown in FIG. 37 is input to the file setting area 3609 and set for the gradation point data for each color attribute. The gradation data can also be set. Reference numeral 3610 denotes a reference button for referring to the file of FIG. By instructing the OK button 3611, the RGB hue values designated in any of the above settings are set in the memory area of the hue data memory 604 or the memory area of the gradation point data memory 610. Further, by instructing a cancel button 3612, the value input so far is deleted, and the previously set hue value is set. The same applies to the change of the set hue value in G and B.
[0162]
Reference numeral 3613 denotes a U / I for changing the set hue in the CMY color attribute, and reference numeral 3614 denotes a U / I for changing the set hue for an arbitrary color attribute of the user.
[0163]
FIG. 38 is a diagram showing an example of a U / I that changes the brightness range condition according to the third embodiment.
[0164]
In the figure, 3801 is a U / I for changing the lightness range condition of RGB. Here, an input display area 3802 for inputting a white point side (WR) lightness ratio to the maximum saturation value, and an input display area for inputting a saturation ratio, which are used when changing the red lightness range condition. 3803, an input display area 3804 for inputting a lightness ratio on the black point side (R-Bk), and an input display area 3805 for inputting a saturation ratio. In addition, when the default button 3806 is instructed with respect to the input values in the input display areas 3802 to 3805, the values input so far can be canceled and returned to the preset brightness range conditions. Further, by instructing an OK button 3807, the brightness range condition set in the input display areas 3802 to 3805 is stored in the memory area of the brightness range condition data memory 802. Further, by instructing a cancel button 3808, the value inputted so far is canceled, the brightness range condition is set in advance, and the U / I 3801 is closed. The same applies to the change of the set hue value for the other colors G and B.
[0165]
Reference numeral 3809 denotes a U / I for changing the lightness range condition in the CMY color attribute, and reference numeral 3810 denotes a U / I for changing the lightness range condition for an arbitrary color attribute of the user.
[0166]
As described above in detail, using these U / Is, the user inputs according to a color correctable region using a lightness tolerance region based on the shape of the output color space. When the setting of the color correction value is completed, an instruction is given to create a color correction profile based on the color correction value by instructing the U / I (tool) profile creation switch in FIG.
[0167]
Thereafter, according to the color correction value stored in the color correction value storage unit 408, in the profile creation unit 208 having the configuration as shown in FIG. 25, an output is performed based on the mapping point determined in the color correction value by the mapping processing unit. Color correction processing is performed on the printer color gamut information. From the result of this color correction processing, the profile creation unit 208 creates a color correction color profile according to the third embodiment.
[0168]
The color correction process according to the third embodiment will be described with reference to the flowcharts shown in FIGS.
[0169]
FIG. 39 is a flowchart for describing processing for setting color correction information using the UI displayed on the display unit 106.
[0170]
As described above, the evaluation value calculated by the lightness evaluation unit 502 of the color correction target color stored in the evaluation target color data storage unit 501, the reference color, and the lightness tolerance range are calculated, and the evaluation result storage unit 503, respectively. After being stored in the reference / allowable coordinate data memory 504, the color correction value is determined by the user using the U / I 506 shown on the display unit 106 in accordance with the flowchart shown in FIG.
[0171]
First, in step S121, in the memory area and U / I for storing color correction information in the color correction value storage unit 408, the evaluation value data of the evaluation target color, which is the initial value, the reference color, and the lightness tolerance area are set and displayed. initialize. In step S122, the user inputs an input using the color correction pointer of the U / I 506 or a color correction value in the input display area, and acquires target color designation information. Next, the process proceeds to step S123, and when the user inputs with the color correction pointer of the U / I or the color designation information in the display area, the process proceeds to step S124, and the color correction value input in step S123 is acquired in step S122. Based on the color designation information, the corresponding color correction value storage unit 408 stores the color correction value in the color correction value memory area. In step S125, when an OK button is designated, the input of the color correction value by this U / I is terminated. If the OK button is not pressed in step S125 and the cancel button is pressed in step S126, the process proceeds to step S127, the color correction value stored in step S124 is deleted, and the evaluation value data of the evaluation target color that is the initial value is input. The color correction value memory area is initialized.
[0172]
If the OK button is not instructed and the cancel button is not instructed, the process proceeds to step S128, and a standby state is entered until the user inputs the color correction pointer on the U / I or the color correction value is input to the display area. .
[0173]
FIG. 40 is a flowchart for describing profile creation processing when an instruction to create a color correction table is input by the user. This process is executed by the profile creation unit 508 based on the color correction value stored in the color correction value storage unit 408. Hereinafter, a color correction process using a color correction value input using the U / I 506 will be described.
[0174]
First, in step S131, the profile creation unit 408 acquires input color gamut information and output color gamut information for performing color correction processing. In step S132, a color correction target color in the color correction value memory area stored in the color correction value storage unit 408 is selected. In step S133, color correction value information in the color correction value memory area for the color correction target color stored in the color correction value storage unit 408 is acquired. In step S134, the L * a * b * coordinate value of the color correction color is acquired from the color correction value information acquired in step S133, and stored in the color correction value storage unit 408. Next, proceeding to step S135, it is determined whether or not the processing shown in steps S133 to S135 has been performed for all the correction target colors. If not completed, the process returns to step S132 and the above-described processing is repeated.
[0175]
If the L * a * b * coordinates of the color correction color have been calculated for all the correction target colors in step S135, the process proceeds to step S136, and the profile creation unit 508 causes the color correction color L * a * b * of the correction target color to be calculated. Color correction processing is performed based on the coordinates. In step S137, the profile creation unit 508 creates a color correction profile from the result of the color correction process. In step S 138, the created color correction profile is stored in the RAM 103.
[0176]
As described above, according to the third embodiment, when color correction is performed for a certain color, color correction processing that can perform color correction using an appropriate lightness tolerance range based on the shape of the output color space. Can be realized.
[0177]
[Embodiment 4]
In the fourth embodiment, as shown in FIG. 24 of the above-described second embodiment, when obtaining the maximum saturation point data Rc2201 from the gradation point data, the white point is used as the origin information for calculating the saturation. The coordinates 2202, the black point coordinates 2203, and the coordinate plane origin (achromatic color axis) 2204 can be selected, and any one point may be selected in calculating the saturation in the gradation point data.
[0178]
Further, in order to select the white point side gradation point, the saturation Cw is referred with the white point 2202 as the origin, while on the other hand, in order to select the black point side gradation point, the saturation Ck is referred with the black point 2203 as the origin. For example, the origin may be appropriately switched from the choices of the origin.
[0179]
FIG. 41 is a diagram for explaining U / I for changing the saturation calculation condition according to the fourth embodiment.
[0180]
In the figure, reference numeral 4101 denotes a U / I for changing RGB saturation calculation conditions. Here, a selection button for setting the white point 2202 in FIG. 24 as the origin when changing the saturation calculation condition in the case of calculating again the gradation data on the white point side with respect to the maximum saturation chromaticity point Rd of red. 4102, a selection button 4103 for setting the black point 2203 as the origin, and a selection button 4104 for setting the coordinate plane origin (achromatic color axis) 2204 as the origin are displayed. The same applies to the change of the set hue value in G and B.
[0181]
The selection button 4105 for setting the white point 2202 as the origin and the black point 2203 as the origin when setting all the saturation calculation conditions on the white point side and the black point side with respect to the maximum saturation chromaticity point of RGB collectively. A selection button 4106 to be set and a selection button 4107 to set the coordinate plane origin (achromatic color axis) 2204 as the origin are displayed. By instructing the OK button 4108 here, the saturation calculation condition set by the U / I 4101 is set in the saturation acquisition unit. Also, by using a cancel button 4109, the value input so far is canceled, the saturation calculation condition is set in advance, and the U / I 4101 is closed. Reference numeral 4110 denotes a U / I for changing the saturation calculation condition for the CMY color attribute, and reference numeral 4111 denotes a U / I for changing the saturation calculation condition for an arbitrary color attribute of the user.
[0182]
As described above, according to the fourth embodiment, when calculating the lightness tolerance range based on the output color space, the user can set an arbitrary saturation calculation condition. Color correction values can be set.
[Other embodiments]
Note that the present invention can be applied to a system composed of a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), or an apparatus composed of a single device (for example, a copier, a facsimile machine, etc.). It may be applied.
[0183]
Another object of the present invention is to supply a storage medium storing software program codes for realizing the functions of the above-described embodiments to a system or apparatus, and the computer (or CPU or MPU) of the system or apparatus stores the storage medium. Needless to say, this can also be achieved by reading and executing the program code stored in.
[0184]
In this case, the program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the program code constitutes the present invention.
[0185]
As a storage medium for supplying the program code, for example, a floppy (registered trademark) disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a CD-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like is used. I can do it.
Further, by executing the program code read by the computer, not only the functions of the above-described embodiments are realized, but also an OS (operating system) running on the computer based on the instruction of the program code. It goes without saying that a part of the actual processing is performed and the functions of the above-described embodiments are realized by the processing.
[0186]
Further, after the program code read from the storage medium is written to a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, the function expansion is performed based on the instruction of the program code. It goes without saying that the CPU or the like provided in the board or the function expansion unit performs part or all of the actual processing, and the functions of the above-described embodiments are realized by the processing.
[0187]
The embodiment described above can be expressed by the following embodiment.
[0188]
[Embodiment 1] An image processing apparatus for converting a color signal of an input image signal into a color signal of an output image,
Color gamut information storage means for storing color gamut information indicating a reproduction color gamut in an output device that outputs the output image;
Calculating means for calculating a variable range of the color conversion control point based on color signal information using the color gamut information and a predetermined condition;
Color conversion means for performing color conversion of an input image signal based on a color conversion control point set in the variable range calculated by the calculation means;
An image processing apparatus comprising:
[0189]
[Embodiment 2] An image processing apparatus for converting a color signal of an input image signal into a color signal of an output image,
Color gamut information storage means for storing color gamut information indicating a reproduction color gamut in an output device that outputs the output image;
Color gamut information display means for displaying color gamut information according to color signal information specified from the color gamut information of the output device;
Display means for calculating and displaying a variable range of color conversion control points based on the color gamut information displayed on the color gamut information display means and a predetermined condition;
Evaluation value determining means for obtaining an evaluation value of a color conversion control point using a color conversion control point set within a variable range of the color conversion control point and a variable range of the color conversion control point;
Color conversion means for performing color conversion of an input image signal based on a color conversion control point set in the variable range;
An image processing apparatus comprising:
[0190]
[Embodiment 3] The image according to Embodiment 1 or 2, wherein the color signal information is color signal data having a predetermined hue in the color gamut information and having a maximum saturation. Processing equipment.
[0191]
[Embodiment 4] The image processing apparatus according to Embodiment 3, wherein the color signal data is extracted based on a distance between a color coordinate and an achromatic color axis in a color space of the color signal data.
[0192]
[Embodiment 5] The color signal data is extracted based on a distance between a color coordinate in a color space of the color signal data and a color coordinate of white output data of the output device or a color coordinate of black output data. The image processing apparatus according to Embodiment 3, wherein the image processing apparatus is characterized.
[0193]
[Embodiment 6] The image processing apparatus according to Embodiment 1 or 2, wherein the predetermined condition is set for each of the designated color signal information.
[0194]
[Embodiment 7] The image processing apparatus according to Embodiment 1 or 2, wherein the predetermined condition is a saturation ratio or a brightness ratio with respect to a color coordinate in a color space of the designated color signal information.
[0195]
[Embodiment 8] The image processing apparatus according to Embodiment 1 or 2, wherein the color gamut information of the output device includes outermost data of the color gamut of the output device.
[0196]
[Embodiment 9] The image processing apparatus according to Embodiment 2, further comprising a maximum saturation point information display unit that displays maximum saturation point information of color gamut information according to the color signal information.
[0197]
[Embodiment 10] The saturation information used in the maximum saturation point information display means is extracted based on a distance between a color coordinate and an achromatic color axis in a color space of the color signal data. The image processing apparatus according to aspect 9.
[0198]
[Embodiment 11] An image processing method for converting a color signal of an input image signal into a color signal of an output image,
A calculation step of calculating a variable range of a color conversion control point based on color signal information using color gamut information indicating a reproduction color gamut in an output device that outputs the output image and a predetermined condition;
A color conversion step of performing color conversion of the input image signal based on the color conversion control point set in the variable range calculated in the calculation step;
An image processing method comprising:
[0199]
[Embodiment 12] An image processing method for converting a color signal of an input image signal into a color signal of an output image,
A color gamut information display step for displaying color gamut information according to color signal information designated from color gamut information indicating a reproduction color gamut in an output device that outputs the output image;
Based on the color gamut information displayed in the color gamut information display step and a predetermined condition, a display step of calculating and displaying a variable range of the color conversion control point;
An evaluation value determining step for obtaining an evaluation value of the color conversion control point using the color conversion control point set within the variable range of the color conversion control point and the variable range of the color conversion control point;
A color conversion step of performing color conversion of an input image signal based on a color conversion control point set in the variable range;
An image processing method comprising:
[0200]
[Embodiment 13] The image according to embodiment 11 or 12, wherein the color signal information is color signal data having a predetermined hue in the color gamut information and having maximum saturation. Processing method.
[0201]
[Embodiment 14] The image processing method according to Embodiment 13, wherein the color signal data is extracted based on a distance between a color coordinate and an achromatic color axis in a color space of the color signal data.
[0202]
[Embodiment 15] The color signal data is extracted based on a distance between a color coordinate in a color space of the color signal data and a color coordinate of white output data of the output device or a color coordinate of black output data. The image processing method according to claim 13, wherein the image processing method is characterized.
[0203]
[Embodiment 16] The image processing method according to embodiment 11 or 12, wherein the predetermined condition is set for each of the designated color signal information.
[0204]
[Embodiment 17] The image processing method according to Embodiment 11 or 12, wherein the predetermined condition is a saturation ratio or a brightness ratio with respect to color coordinates in a color space of the designated color signal information.
[0205]
[Embodiment 18] The image processing method according to Embodiment 11 or 12, wherein the color gamut information of the output device includes outermost data of the color gamut of the output device.
[0206]
[Embodiment 19] The image processing method according to Embodiment 12, further comprising the step of displaying maximum saturation point information of color gamut information according to the color signal information.
[0207]
[Aspect 20] The image processing method according to Aspect 19, wherein the maximum saturation point information is extracted based on a distance between a color coordinate and an achromatic color axis in a color space of the color signal data. .
[0208]
As described above, according to the present embodiment, when the color signal of the input image is converted into the color signal of the output image, the target color signal, the color signal information corresponding to the visual characteristics, and the output color space Color conversion using a brightness target based on the shape can be performed. Accordingly, there is an effect that it is possible to realize color reproduction in which the color of the primary color and the entire mapping result are optimized when viewed by a person.
[0209]
Further, according to the present embodiment, when the color signal of the input image is converted into the color signal of the output image, the target color signal, the color signal information corresponding to the visual characteristics, and the brightness based on the shape of the output color space By performing color conversion using the allowable range and the lightness allowable evaluation value, there is an effect that it is possible to realize color reproduction that optimizes the color of the primary color and the entire mapping result when viewed by a person.
[0210]
【The invention's effect】
As described above, according to the present invention, the mapping chromaticity point with respect to a predetermined color signal in the lightness range determined based on the equi-hue line information for human vision, the lightness condition, and the saturation condition. By performing the color conversion in which is set, the color reproduction that optimizes the color and the entire mapping result can be realized.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to Embodiment 1 of the present invention.
FIG. 2 is a block diagram showing a configuration of an image processing unit according to the first embodiment.
FIG. 3 is a flowchart illustrating an operation of a mapping parameter calculation unit according to the first embodiment.
FIG. 4 is a flowchart for explaining mapping processing in a color gamut mapping unit according to the first embodiment;
FIG. 5 is a diagram illustrating a relationship between saturation and lightness in red (R).
6 is a block diagram showing a functional configuration of a gradation point information setting unit of a mapping parameter calculation unit according to the first embodiment. FIG.
FIG. 7 is a flowchart for explaining processing of a gradation point information setting unit of the mapping parameter calculation unit according to the first embodiment.
FIG. 8 is a diagram illustrating a data configuration example of a hue data memory.
FIG. 9 is a diagram illustrating an example of an equi-hue line data memory set in the present embodiment.
FIG. 10 is a diagram illustrating a data configuration example of an equi-hue line data memory in red of a gradation point data memory storing all calculated intersection coordinates.
FIG. 11 is a diagram illustrating a result based on processing according to the present embodiment.
FIG. 12 is a block diagram illustrating a configuration of a brightness range setting unit of a mapping parameter calculation unit according to the present embodiment.
FIG. 13 is a flowchart illustrating an operation of a brightness range setting unit according to the first embodiment.
FIG. 14 is a diagram for explaining a method for obtaining a lightness range A based on a saturation condition for maximum saturation.
FIG. 15 is a diagram for explaining a data configuration example stored in a brightness range condition data memory according to the present embodiment;
FIG. 16 is a diagram illustrating a method for obtaining a lightness range B from lightness conditions for a maximum saturation point Rd.
FIG. 17 is a diagram illustrating an example of a relationship between a lightness range A and a lightness range B according to the first embodiment.
FIG. 18 is a diagram showing an example of a lightness tolerance range data memory that stores all of the lightness tolerance range data according to the embodiment of the present invention.
FIG. 19 is a block diagram showing a configuration of a color gamut mapping unit according to the first embodiment.
FIG. 20 illustrates an operation for obtaining a mapping point for a sample point from the gradation point and the lightness range stored in the gradation point information setting unit and the lightness range setting unit by the color gamut mapping unit according to the first embodiment. It is a flowchart.
FIG. 21 is a flowchart illustrating processing for determining a mapping point for a primary color target sample point in step S88 of FIG. 20;
FIG. 22 is a diagram illustrating an example in which the target brightness of the primary color mapping point is set within a brightness tolerance range.
FIG. 23 is a diagram illustrating an example in which a primary color mapping point is obtained and stored in an output data memory.
FIG. 24 is a diagram illustrating Embodiments 2 and 4 of the present invention.
FIG. 25 is a block diagram showing a configuration of a profile creation processing unit according to the third embodiment of the present invention.
FIG. 26 is a flowchart for explaining the operation of a mapping parameter calculation unit according to the third embodiment.
FIG. 27 is a block diagram illustrating a functional configuration of an image processing unit according to the third embodiment.
FIG. 28 is a diagram for explaining a data configuration example of a reference / brightness tolerance area coordinate data memory according to the third embodiment;
FIG. 29 is a diagram showing an example of a data configuration in an evaluation result storage unit that stores evaluation values and evaluation results according to the third embodiment.
FIG. 30 is a flowchart illustrating a process in which the brightness evaluation unit according to the third embodiment performs position determination of the brightness tolerance range of the brightness of the evaluation target color.
FIG. 31 is a diagram showing an example of a U / I screen on which a user can specify a color correction amount in the color correction processing according to the third embodiment.
FIG. 32 is a diagram illustrating a data configuration example of a color correction value storage unit that stores color correction values.
FIG. 33 is a diagram illustrating a display example of a window displaying a mapping result.
FIG. 34 is a diagram showing a display example of a window for the user to set mapping conditions.
FIG. 35 is a diagram showing an example of a file storing coordinate values of target L * a * b * of a color conversion result for input RGB data according to the third embodiment.
FIG. 36 is a diagram illustrating an example of a U / I that allows a user to arbitrarily set a hue with respect to color attribute information.
FIG. 37 is a diagram showing an example of a file storing gradation point data arbitrarily determined by a user.
FIG. 38 is a diagram showing an example of a U / I that changes a lightness range condition according to Embodiment 3 of the present invention.
FIG. 39 is a flowchart illustrating processing for setting color correction information using a UI displayed on a display unit according to the third embodiment.
FIG. 40 is a flowchart for describing profile creation processing when a user inputs a color correction table creation instruction;
FIG. 41 is a diagram for explaining U / I for changing the saturation calculation condition according to the fourth embodiment.

Claims (10)

An image processing apparatus that converts a color signal of an input image signal into a color signal of an output image,
And gamut information storage means for storing color gamut information indicating a color reproduction gamut in the output device for outputting the output image,
The lightness divided for the color gamut information indicating the color gamut in the output device is set, the equi-hue line is obtained for each lightness, and the equi-hue line for each lightness and the color gamut in the output device Determining means for determining gradation point information that is an intersection with the outline of
The gradation point on the white point side and the black point side as viewed from the point of the maximum saturation, which satisfies the saturation condition and the lightness condition predetermined for the maximum saturation for the predetermined hue in the color gamut information. Calculating means for obtaining each lightness of information and calculating a lightness tolerance range according to each lightness of the gradation point information on the white point side and the black point side ;
Color conversion means for mapping the input image signal of the predetermined hue to the lightness tolerance range calculated by the calculation means;
An image processing apparatus comprising: The image processing apparatus according to claim 1, wherein there are a plurality of the predetermined hues, and the saturation condition is provided for each of the plurality of hues. The image processing apparatus according to claim 1, wherein a lightness range that satisfies the saturation condition and a common lightness range of the lightness ranges that satisfy the lightness condition are the lightness tolerance range. The predetermined hue is a plurality of primary colors, the input image signal of the predetermined hue is mapped, and the mapping point of the input image signal of the predetermined hue to the color gamut in the output device is obtained. The image processing apparatus according to claim 1. 5. The image processing apparatus according to claim 4, further comprising means for evaluating a mapping point of the input signal having the predetermined hue. Image processing of an image processing apparatus having color gamut information storage means for storing color gamut information indicating a color reproduction color gamut in an output device that outputs an output image, and converting a color signal of an input image signal into a color signal of an output image A method,
The lightness divided for the color gamut information indicating the color gamut in the output device is set, the equi-hue line is obtained for each lightness, and the equi-hue line for each lightness and the color gamut in the output device A determination step of determining gradation point information that is an intersection with the outline of
The gradation point on the white point side and the black point side as viewed from the point of the maximum saturation, which satisfies the saturation condition and the lightness condition predetermined for the maximum saturation for the predetermined hue in the color gamut information. A calculation step of obtaining each lightness of the information and calculating a lightness tolerance range according to each lightness of the gradation point information on the white point side and the black point side;
A color conversion step for mapping the input image signal of the predetermined hue to the lightness tolerance range calculated in the calculation step;
An image processing method comprising: The image processing method according to claim 6, wherein there are a plurality of the predetermined hues, and the saturation condition is provided for each of the plurality of hues. The image processing method according to claim 6, wherein a lightness range that satisfies the saturation condition and a common lightness range of the lightness ranges that satisfy the lightness condition are the lightness tolerance range. The predetermined hue is a plurality of primary colors, and the input image signal of the predetermined hue is copied. The image processing method according to claim 6, wherein an image is performed, and a mapping point of the input image signal of the predetermined hue to a color gamut in the output device is obtained. The image processing method according to claim 9, further comprising evaluating a mapping point of the input signal having the predetermined hue.

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