JP2010103733A - Color conversion table generating device, color conversion table, and image processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a color conversion table generating device capable of creating a color conversion table which can perform color conversion processing that maintains color conversion precision of an area with a lattice point added thereto. <P>SOLUTION: When first color data is associated with second color data obtained by converting the first color data to be a color conversion data pair and a second color conversion table including the predetermined number of color conversion data pairs is created, first of all, a first color conversion table generating part 1 generates a first color conversion table where the number of color conversion data pairs is smaller than that of the second color conversion table. An area specifying part 2 specifies a color area where color conversion pairs are added about the first color conversion table. A color conversion data pair adding part 3 adds a color conversion data pair to the color area specified by the area specifying part 2. A second color table creating part 4 creates a second color conversion table including the predetermined number of color conversion data pairs by interpolation on the basis of the first color conversion table with the color conversion table pairs added thereto. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a color conversion table generation device, a color conversion table, and an image processing device.

  As one of the processes for the color image, a color conversion process is performed. As one method of this color conversion processing, there is a method using a color conversion table in which color conversion data pairs in which first color data before conversion and second color data after conversion are associated are registered in advance. In this color conversion table, registering the second color data corresponding to all the first color data requires a large storage capacity. Therefore, some first color data are selected. A color conversion data pair is obtained and registered. For the color data other than the registered first color data, the corresponding second color data is obtained from the plurality of registered first color data whose distances are close in the color space, and interpolation is performed. The color data after conversion is calculated.

  The color conversion data pair registered in the color conversion table divides the range of possible values for each color component constituting the first color data by a predetermined number of divisions, and sets one of the division points of each color component. The first color data obtained by the combination and the second color data after the conversion of the first color data. FIG. 11 is an explanatory diagram of an example of first color conversion data registered in the color conversion table. The first color data of the color conversion data pair registered in the color conversion table as described above is a color point indicated by a black circle in FIG. 11 in the color space of the first color data. As shown in the drawing, these color points are called lattice points because they are apparently color points at the intersections of the lattices.

  Since the color data after conversion is obtained by interpolation for the first color data other than the grid points, the color conversion accuracy generally depends on the number of grid points. However, the process for accurately obtaining the second color data corresponding to the first color data is a process that requires a large amount of calculation and takes time. Further, if the number of grid points is increased, the storage capacity is required accordingly. Therefore, conventionally, the number of divisions of each color component is determined in consideration of these conditions, and a color conversion table is created by obtaining color conversion data pairs at lattice points.

  As a conventional technique for increasing / decreasing the number of color conversion data pairs to be registered in the color conversion table, for example, in Patent Document 1, color conversion data pairs are generated by interpolation from a certain number of color conversion tables to increase the number of registrations. A color conversion table is created.

  For example, in Patent Document 2 and Patent Document 3, a color conversion table in which the number of registrations is reduced is generated by thinning out a color conversion table created in advance.

  Further, for example, in Patent Document 4, when the range of possible values of each color component is divided, it is divided with an unequal width, and the division width is narrowed for an area that requires color conversion accuracy in the color space, and the color conversion accuracy is reduced. It is described that a color conversion table in which the division width is widened and the number of grid points is reduced as a whole is used for an area where no is required.

Japanese Patent Laid-Open No. 10-191090 JP-A-10-173951 Japanese Patent Laid-Open No. 2004-23739 JP 2005-244620 A

  The present invention provides a color conversion table generation device capable of creating a color conversion table capable of color conversion processing while maintaining the color conversion accuracy of an area to which grid points are added, as compared to an invention that does not specify an area for which accuracy is to be determined, and It is an object of the present invention to provide a created color conversion table and an image processing apparatus that performs color conversion using the color conversion table.

  The invention according to claim 1 of the present application includes a smaller number of color conversion data pairs in which the first color data and the second color data obtained by converting the first color data are associated with each other. An area specifying means for specifying a color area to which a color conversion data pair is added for the first color conversion table, and the color conversion data pair in the color area specified by the area specifying means are added to the first color conversion table. And a second color conversion table including a predetermined number of color conversion data pairs by interpolation based on the first color conversion table to which the color conversion data pairs have been added by the adding means. A color conversion table generating apparatus having a creating means for creating.

  The invention according to claim 2 of the present application is characterized in that the area specifying means in the color conversion table generating device according to claim 1 specifies the color area according to the amount of change in the second color data. It is a color conversion table generation device.

  According to a third aspect of the present invention, in the color conversion table generating device according to the first aspect of the present invention, the area specifying means includes one of the two second color data constituting the second color data. The color conversion table generating apparatus is characterized in that the color region is specified based on whether or not a value of at least one color component is a minimum value or a maximum value.

  The invention according to claim 4 of the present application further includes generation means for generating the first color conversion table in addition to the configuration of the color conversion table generation apparatus according to any one of claims 1 to 3. A color conversion table generating device characterized by having the color conversion table.

  According to a fifth aspect of the present invention, in the color conversion table generating device according to the fourth aspect of the present invention, the generation means changes the interval of the first color data according to the lightness. Device.

  In the invention according to claim 6 of the present application, the first color data and the second color data obtained by converting the first color data are associated with each other as a color conversion data pair, which is smaller in number than the predetermined number. Generating means for generating a first color conversion table including color conversion data pairs; and second color conversion including a predetermined number of the color conversion data pairs by interpolation based on the first color conversion table Creating means for creating a table, wherein the generating means arranges the first color data according to color conversion accuracy for each region in a color space of the first color data, and The color conversion table generation device generates the first color conversion table including the color conversion data pair corresponding to data.

  According to a seventh aspect of the present invention, in the color conversion table generating device according to the sixth aspect of the present invention, the generation means changes the interval of the first color data according to lightness. Device.

  The invention according to claim 8 is the first color including the first color data and the second color data obtained by converting the first color data, the number of which is smaller than the number of color conversion data pairs associated with each other. A color area to which a color conversion data pair is added is specified in the conversion table, the color conversion data pair in the color area is added to the first color conversion table, and the color conversion data pair is added to the first color It is a color conversion table created so as to include a predetermined number of the color conversion data pairs obtained by interpolation based on the conversion table.

  The invention according to claim 9 includes color conversion means for converting the first color signal into the second color signal using a color conversion table including a predetermined number of the color conversion data pairs. The color conversion table is a first color conversion table including a smaller number than the number of color conversion data pairs in which the first color data and the second color data obtained by converting the first color data are associated with each other. The color conversion data pair to be added is specified, the color conversion data pair in the color area is added to the first color conversion table, and the color conversion data pair is added to the first color conversion table. An image processing apparatus created so as to include a predetermined number of the color conversion data pairs originally obtained by interpolation.

  According to the first aspect of the present invention, a color conversion table capable of reducing the amount of calculation and performing color conversion processing while maintaining color conversion accuracy is created as compared with the invention that does not specify a region where color conversion accuracy deteriorates. can do.

  According to the second aspect of the present invention, the color conversion accuracy can be improved according to the amount of change in the second color data, as compared with the invention without this configuration.

  According to the third aspect of the present invention, it is possible to improve the color conversion accuracy in the color gamut outline as compared with the invention not having this configuration.

  According to the invention described in claim 4 of the present application, it is possible to perform a color conversion process that reduces the amount of calculation and maintains the color conversion accuracy even in the absence of the first color conversion table as compared with the invention that does not have this configuration. A second color conversion table can be created.

  According to the invention described in claim 5 of the present application, the amount of calculation from the stage of creating the first color conversion table is reduced in consideration of the difference in color conversion accuracy according to the lightness compared to the invention not having this configuration. be able to.

  According to the sixth aspect of the present invention, it is possible to create a color conversion table capable of performing color conversion processing while reducing the amount of calculation and maintaining the color conversion accuracy as compared with the invention not having this configuration.

  According to the seventh aspect of the present invention, it is possible to create the second color conversion table in consideration of the difference in color conversion accuracy according to the lightness.

  According to the invention described in claim 8 of the present application, it is possible to perform color conversion processing while maintaining color conversion accuracy, compared to an invention that does not specify a region where color conversion accuracy deteriorates.

  According to the invention described in claim 9 of the present application, it is possible to perform color conversion processing while maintaining the color conversion accuracy, as compared with the invention in which the region where the color conversion accuracy deteriorates is not specified.

  FIG. 1 is a configuration diagram showing an embodiment of the present invention. In the figure, 1 is a first color conversion table generating unit, 2 is an area specifying unit, 3 is a color conversion data pair adding unit, and 4 is a second color conversion table generating unit. Here, the first color data and the second color data obtained by converting the first color data are associated with each other to form a color conversion data pair, and a second color conversion including a predetermined number of color conversion data pairs Create a table. For example, as shown in FIG. 11, the color conversion data pair may be obtained at the grid points when the color components of the first color data are divided at predetermined intervals.

  The first color conversion table generation unit 1 generates a first color conversion table including fewer color conversion data pairs than the second color conversion table to be created. The color conversion data pairs included in the first color conversion table may be, for example, color conversion data pairs of some lattice points among the lattice points included in the second color conversion table. Of course, a first color conversion table having a grid point different from that of the second color conversion table may be generated. Further, the color conversion data pair corresponding to the area is obtained, for example, the grid point is thinned out according to the lightness to change the interval of the first color data so that the color conversion data pair is not generated in the area where the lightness change is not noticeable. May be registered in the first color conversion table.

  A known method may be used as a method of obtaining the color conversion data pair included in the first color conversion table. For example, a pair of a color actually given to a certain input / output device and the obtained color is used. Then, a color conversion model is created, and first color data to be grid points is given to the color conversion model to obtain second color data. The process for obtaining the color conversion data pair requires a calculation amount and a processing time. If the first color conversion table already exists, the first color conversion table generation unit 1 may be omitted.

  The area specifying unit 2 adds a color conversion data pair to the first color conversion table and specifies a color area for improving the color conversion accuracy. For example, the color region to which the color conversion data pair is added may be specified according to the amount of change in the two second color data. More specifically, when the difference in the second color data between the grid points is larger than a predetermined value, it may be determined as a color region to which a color conversion data pair is added. In addition, for example, one of the two second color data is added with a color conversion data pair depending on whether the value of at least one color component constituting the second color data is the minimum value or the maximum value. The color area to be specified may be specified. Furthermore, since an area including the color gamut outline is required to have color conversion accuracy, it may be specified as a color area to which a color conversion data pair is added even in such a case.

  The color conversion data pair adding unit 3 adds a color conversion data pair to the first color conversion table in the color region specified by the region specifying unit 2. As described above, since the color area specified by the area specifying unit 2 is estimated to have no color conversion accuracy by the interpolation processing performed by the second color conversion table creating unit 4, the color conversion data is stored in this area. Improve color conversion accuracy by adding pairs. For example, the method used for generating the first color conversion table in the first color conversion table generating unit 1 may be applied to the color conversion data pair to be added. Even when the first color conversion table generation unit 1 is not provided, the color conversion data pair may be obtained using the method exemplified in the first color conversion table generation unit 1.

  The second color conversion table creation unit 4 includes a number of color conversion data pairs that are determined in advance by interpolation based on the first color conversion table in which the color conversion data pair addition unit 3 adds the color conversion data pairs. Create a two-color conversion table. Thereby, a desired color conversion table is obtained.

  FIG. 2 is a flowchart showing an example of the operation in the embodiment of the present invention, and FIG. 3 is an explanatory diagram of an example of the color conversion data pair registered in each color conversion table in the color space of the first color data. Here, a second color conversion table including a color conversion data pair of the first color data and the second color data corresponding to the first color data for the lattice points indicated by black circles in FIG. To get. In FIG. 3, the color space of the first color data is illustrated as being the CIELAB color space, but the color space of the first color data is not limited to this example.

  In S51, a first color conversion table having a smaller number of color conversion data pairs than the second color conversion table is prepared. For example, it may be generated by the first color conversion table generation unit 1. Here, as an example, for a grid point indicated by a black circle in FIG. 3A, a color conversion data pair of the first color data and the second color data corresponding to the first color data is the first color conversion table. Shall be registered.

  In S52, the area specifying unit 2 specifies a color area to which a color conversion data pair is added for the first color conversion table prepared in S51. A specific example will be described later. In S53, the color conversion data pair adding unit 3 adds the color conversion data pair to the first color conversion table in the color area specified by the area specifying unit 2. In FIG. 3B, it is assumed that the area specifying unit 2 adds a color conversion data pair for a color area including a white circle, and the color conversion data pair adding unit 3 corresponds to the first color data indicated by a white circle. It is assumed that a color conversion data pair to be added is added.

  In S54, the second color conversion table creation unit 4 includes a second color conversion data pair including a predetermined number of color conversion data pairs by interpolation based on the first color conversion table after the color conversion data pairs are added in S53. Create a color conversion table. In the example shown in FIG. 3, the first color indicated by the black circle in FIG. 3C is based on the color conversion data pair corresponding to the first color data indicated by the black circle and the white circle in FIG. The second color data in the data is calculated by interpolation, a color conversion data pair of the first color data and the second color data is obtained, and a second color conversion table is created.

  Processing that requires a calculation amount and processing time is processing for obtaining a color conversion data pair corresponding to the first color data indicated by the white circles or black circles and white circles shown in FIG. Processing does not require calculation amount and processing time. Therefore, according to the embodiment of the present invention, the calculation amount and the processing time are reduced as compared with the case where the color conversion data pairs corresponding to the first color data indicated by the black circles in FIG. Will do. In addition, since the color conversion data pair is added to the color region to which the color conversion data pair is added, the color conversion processing using the second color conversion table is performed with high accuracy.

  The processing of the area specifying unit 2 and the color conversion data pair adding unit 3 will be further described. 4 and 5 are explanatory diagrams of an example of the area determination process based on the difference in the second color data. Here, the color space of the second color data is CMYK, the position of the first color data in the color space is the horizontal axis, and the value of the second color data at that position is the vertical axis. ing. The black circles in the figure indicate the values of the second color data of the color conversion data pairs registered in the first color conversion table. The double circle indicates the value of the second color data obtained by interpolation, and the white circle indicates the value of the second color data when the color conversion data pair is added by the color conversion data pair adding unit 3. .

  For example, the difference of the second color data is obtained for the color conversion data pairs of two adjacent grid points. The example shown in FIG. 4A shows a case where the difference in the values of the second color data indicated by black circles is smaller than a preset value. When the value of the second color data is obtained by interpolation at the intermediate position between the two positions indicated by the black circles, the value indicated by the double circle is obtained. When the color conversion data pair is obtained, the value of the second color data is The value is indicated by a white circle. In this case, even if the value of the second color data is obtained by interpolation, the color conversion accuracy is not lowered. Therefore, this area is determined to be an area where the color conversion accuracy is maintained, and the color conversion data pair adding unit 3 does not add the color conversion data pair.

  The example shown in FIG. 4B shows a case where the difference between the values of the second color data indicated by black circles is larger than a preset value. When the value of the second color data is obtained by interpolation at the intermediate position between the two positions indicated by the black circles, the value indicated by the double circle is obtained. When the color conversion data pair is obtained, the value of the second color data is The value is indicated by a white circle. In this case, the value of the second color data obtained by interpolation is different from the value of the second color data when the color conversion data pair is obtained, and there is a possibility that a difference in color is recognized. In such a case, it is determined that this area is an area to which a color conversion data pair is added, and the color conversion data pair adding unit 3 adds the color conversion data pair. For example, as shown by a white circle in FIG. 4B, the color conversion data pair to be added has first color data set in the middle of the first color data of the color conversion data pair to be determined. It only has to be obtained. Of course, a color conversion data pair corresponding to the first color data other than the intermediate color data may be added. For example, the number of color conversion data pairs to be added may be changed according to the difference in the values of the second color data. Further, as described above, after being added to the middle position of the first color data, the region determination and the addition of the color conversion data pair are performed recursively including the added color conversion data pair. Also good.

  Note that, as the difference between the second color data, a color difference may be used, and each difference may be used for each color component of the second color data. In the case of using a difference for each color component, it is preferable that a color conversion data pair is added to the area if even one color component having a difference larger than a preset value exists.

  In the example shown in FIG. 5, the case where one of the second color data has the maximum value is shown. In color conversion, the color range of the first color data may be different from the color range of the second color data. In such a case, it is assumed that the second color data also changes as indicated by the thick dotted line in the figure in accordance with the change in the first color data. However, due to the limitation of the color range of the second color data. The second color data is limited by the maximum value.

  FIG. 5 shows such a state, and one of the two second color data indicated by black circles has a maximum value. In this case, when the value of the second color data is obtained by interpolation at the middle position between the two positions indicated by the black circles, the value indicated by the double circle is obtained, and the second color data when the color conversion data pair is obtained is obtained. The value of is a value indicated by a white circle. In this example, the value of the second color data when the color conversion data pair indicated by the white circle is obtained is also the maximum value.

  When one of the two second color data values to be compared is the maximum value, the color change tendency is changed. Therefore, it is determined that the color conversion data pair is added and the color conversion is performed. The data pair adding unit 3 adds a color conversion data pair. The color conversion data pair to be added is preferably a color conversion data pair at a boundary point where the value of the second color data is the maximum value. However, as shown in FIG. The color conversion data pair may be obtained by setting the first color data in the middle of the first color data of the data pair. Of course, in this case as well, a plurality of color conversion data pairs may be added, or region determination and color conversion data pair addition processing may be performed recursively. Further, whether the value of the second color data is the maximum value or not is that the value of the second color data is the maximum value if at least one of the color components constituting the second color data is the maximum value. What is necessary is just to judge. Here, the case where one of the two second color data values is the maximum value has been described, but the area to which the color conversion data pair is added even when one of the two second color data values is the minimum value The color conversion data pair adding unit 3 may add the color conversion data pair.

  FIG. 6 is an explanatory diagram of an example in which processing for adding a color conversion data pair according to lightness is performed. For example, an area to which a color conversion data pair is to be added may be specified according to lightness, and the color conversion data pair may be added to that area. In the example illustrated in FIG. 6, a color conversion data pair is added to a color area having a predetermined first brightness or higher, or a color area having a second brightness lower than the first brightness. As a result, a color conversion data pair may be added. The color region having the first brightness or more is a color region in which color change is conspicuous and color conversion accuracy is required. The color area below the second lightness is a color area that requires color conversion accuracy when determining the value of each color component of the second color data.

  As described above, the color conversion data pair is added to the color area having the first lightness or higher and the color area having the second lightness or lower, and the addition ratio of the color conversion data pair may be changed according to the lightness. Good.

  FIG. 7 is an explanatory diagram of an example in which color conversion data pair addition processing is performed on the color gamut outline of the second color data. Although the case where the value of the second color data is the maximum value is included, since the color conversion accuracy is required for the outline of the color reproduction range reproduced by the second color data, the color conversion data pair is A color conversion data pair may be added as a region to be added. In the example shown in FIG. 7, a cross section at a certain hue angle in the color space of the first color data is shown, and a broken line represents a color reproduction range reproduced by the second color data. This is the outline when shown in space. When this outline exists between two color conversion data pairs, it is determined that the color conversion data pair is to be added, and the color conversion data pair may be added as indicated by a white circle in FIG. 7B.

  In addition to this, it is also possible to specify a region to which a color conversion data pair is added under various conditions and add the color conversion data pair.

  FIG. 8 is a block diagram showing a modification of the embodiment of the present invention. In the above description, after the first color conversion table generation unit 1 generates the first color conversion table, the region is determined and necessary color conversion data is added. As a modification, when the first color conversion table generating unit 1 generates the first color conversion table, a color conversion data pair may be generated for an area that requires a known color conversion accuracy. Conceivable. For example, when adding the number of color conversion data pairs according to lightness as in the example illustrated in FIG. 6, the first color conversion table generating unit 1 generates the first color conversion table according to the lightness. It is sufficient to generate a number of color conversion data pairs. Further, for example, if the color gamut outline is known to some extent as in the example shown in FIG. 7, the first color conversion table may be generated by increasing the number of color conversion data pairs around the color gamut outline.

  In this way, if the first color conversion table generated by the first color conversion table generation unit 1 includes a color conversion data pair to be added for an area requiring a known color conversion accuracy, for example, FIG. The area specifying unit 2 and the color conversion data pair adding unit 3 may be configured not to operate in the configuration shown in FIG.

  FIG. 9 is a configuration diagram illustrating an application example in which color conversion processing is performed using the obtained color conversion table. In the figure, 11 is a color conversion unit, and 12 is a color conversion table. Here, as the color conversion table 12, the second color conversion table created in the above-described configuration and its modification is used.

  The color conversion unit 11 uses the color conversion table 12 to color-convert the input first color signal into a second color signal. More specifically, one or more converted color signals are obtained from the color conversion table 12 based on the first color signal, and interpolation processing is performed when a plurality of converted color signals are obtained. The second color signal may be used. For example, this configuration may be installed in a printer, a copier, a facsimile machine, or the like to perform color conversion.

  FIG. 10 is an explanatory diagram of an example of a computer program, a storage medium storing the computer program, and an example of a computer when the functions described in the embodiment of the present invention or its modifications and application examples are realized by a computer program. . In the figure, 21 is a program, 22 is a computer, 31 is a magneto-optical disk, 32 is an optical disk, 33 is a magnetic disk, 34 is a memory, 41 is a CPU, 42 is an internal memory, 43 is a reading unit, 44 is a hard disk, 45 is An interface 46 is a communication unit.

  A part or all of the functions of the units described in the above-described embodiment of the present invention, the modified example thereof, and the application example may be realized by a program 21 that can be executed by a computer. In that case, the program 21, the data used by the program, the data of the created color conversion table, and the like may be stored in a computer-readable storage medium. The storage medium refers to the reading unit 43 provided in the hardware resource of the computer, causing a change state of energy such as magnetism, light, electricity, etc. according to the description content of the program, and corresponding signals. In this format, the description content of the program is transmitted to the reading unit 43. For example, there are a magneto-optical disk 31, an optical disk 32 (including a CD and a DVD), a magnetic disk 33, a memory 34 (including an IC card, a memory card, and the like). Of course, these storage media are not limited to portable types.

  The program 21 is stored in these storage media, and the program 21 is read from the computer and stored in the internal memory 42 or the hard disk 44 by, for example, mounting these storage media on the reading unit 43 or the interface 45 of the computer 22. By executing the program 21 by the CPU 41, a part or all of the functions described in the above-described embodiment of the present invention, the modification thereof, or the application example is realized. Alternatively, the program 21 is transferred to the computer 22 via the communication path, and the computer 22 receives the program 21 by the communication unit 46 and stores it in the internal memory 42 or the hard disk 44, and the CPU 21 executes the program 21. May be.

  In addition, the computer 22 may be connected to various devices via an interface 45. For example, a display unit that displays information, a reception unit that receives information from a user, and the like may be connected. Further, for example, the image forming unit may be connected via the interface 45.

It is a block diagram which shows one Embodiment of this invention. It is a flowchart which shows an example of the operation | movement in one Embodiment of this invention. It is explanatory drawing of an example of the color conversion data pair registered into each color conversion table in the color space of 1st color data. It is explanatory drawing of an example of the area | region determination process by the difference of 2nd color data. It is explanatory drawing of another example of the area | region determination process by the difference of 2nd color data. It is explanatory drawing of an example which performed the addition process of the color conversion data pair according to the brightness. It is explanatory drawing of an example which performed the addition process of the color conversion data pair about the color gamut outline of 2nd color data. It is a block diagram which shows the modification of one Embodiment of this invention. It is a block diagram which shows one application example which performs a color conversion process using the obtained color conversion table. FIG. 15 is an explanatory diagram of an example of a computer program, a storage medium storing the computer program, and a computer when the functions described in the embodiment of the present invention or its modifications and application examples are realized by a computer program. It is explanatory drawing of an example of the 1st color conversion data registered into a color conversion table.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... 1st color conversion table production | generation part, 2 ... Area specification part, 3 ... Color conversion data pair addition part, 4 ... 2nd color conversion table creation part, 11 ... Color conversion part, 12 ... Color conversion table, 21 ... Program , 22 ... Computer, 31 ... Magneto-optical disk, 32 ... Optical disk, 33 ... Magnetic disk, 34 ... Memory, 41 ... CPU, 42 ... Internal memory, 43 ... Reading part, 44 ... Hard disk, 45 ... Interface, 46 ... Communication part .

Claims (9)

  Color conversion data pairs are added to the first color conversion table including a smaller number of color conversion data pairs in which the first color data and the second color data obtained by converting the first color data are associated with each other. Area specifying means for specifying a color area, adding means for adding the color conversion data pair in the color area specified by the area specifying means to the first color conversion table, and adding the color conversion data pair by the adding means A color conversion table comprising: a second color conversion table including a predetermined number of the color conversion data pairs by interpolation based on the first color conversion table to which is added Generator.   The color conversion table generating apparatus according to claim 1, wherein the area specifying unit specifies the color area according to a change amount of the second color data.   The area specifying means determines whether the color area depends on whether one of the two second color data has a minimum value or a maximum value of at least one color component constituting the second color data. The color conversion table generation device according to claim 1, wherein the color conversion table generation device is specified.   4. The color conversion table generation apparatus according to claim 1, further comprising generation means for generating the first color conversion table. 5.   The color conversion table generation apparatus according to claim 4, wherein the generation unit changes an interval of the first color data according to lightness.   Generation of a first color conversion table including a smaller number of color conversion data pairs than the number of color conversion data pairs in which first color data and second color data obtained by converting the first color data are associated with each other And generating means for generating a second color conversion table including a predetermined number of the color conversion data pairs by interpolation based on the first color conversion table, and the generating means The first color data is arranged according to the color conversion accuracy for each region in the color space of the first color data, and includes the first color conversion data pair corresponding to the first color data. A color conversion table generation apparatus characterized by generating a color conversion table.   The color conversion table generation apparatus according to claim 6, wherein the generation unit changes an interval of the first color data according to lightness.   Add color conversion data pairs to the first color conversion table including a smaller number of color conversion data pairs in which the first color data and the second color data converted from the first color data are associated with each other. The color conversion data pair in the color area is identified and added to the first color conversion table, and the color conversion data pair is obtained by interpolation based on the first color conversion table to which the color conversion data pair is added. A color conversion table created so as to include a predetermined number of the color conversion data pairs.   Color conversion means for converting a first color signal into a second color signal using a color conversion table including a predetermined number of the color conversion data pairs, and the color conversion table includes: A color region in which color conversion data pairs are added to a first color conversion table that includes a smaller number than the number of color conversion data pairs in which color data and second color data obtained by converting the first color data are associated with each other. And the color conversion data pair in the color region is added to the first color conversion table, and is determined in advance by interpolation based on the first color conversion table to which the color conversion data pair is added. An image processing apparatus created so as to include a number of the color conversion data pairs.

Images