JP4675155B2 - Color data processing method, color data processing system, color data processing program, and recording medium recording the same - Google Patents

Description

  The present invention relates to a color data processing method for processing color data, a color data processing system, a color data processing program, and a recording medium recording the same.

There is known a color gamut mapping apparatus that maps a color reproduced by one device to a color within the color gamut of the other device when the color is reproduced by a plurality of devices having different color gamuts. In this type of color gamut mapping apparatus, it is known to perform color gamut mapping using a cusp that is the highest saturation point for each hue (see Patent Document 1).
Patent Document 2 discloses a color image signal processing apparatus that sets a color gamut in accordance with a cusp brightness difference between devices in a predetermined hue.

JP 2004-32140 A JP 2003-153018 A

However, in the above conventional example, a cusp calculation method is not disclosed. In addition, in order to obtain a cusp for each hue, if the cusp is calculated on the intersection line between the L ^* -C ^* (brightness-saturation) plane and the color gamut outline in the target hue, Will increase.

  Therefore, the present invention provides a color data processing method, a color data processing system, a color data processing program, and a recording medium recording the same, which can easily acquire a cusp having the highest saturation for each hue in a predetermined color space. The purpose is to provide.

In order to achieve the above object, a first feature of the present invention is a color data processing method for mapping color data in a device-dependent color space to a device-independent color space. A plurality of cusps having the highest saturation for each hue in the device-independent color space are identified in the device-dependent color space from the data, and the identified plurality of cusps are devices in the device-dependent color space A plurality of cusps including cusps other than the vertices of the color gamut outline are identified as cusp sequences, the identified cusp sequences are mapped to the device-independent color space, and are included in the cusp sequence mapped to the device-independent color space The color data processing method interpolates between each of the plurality of cusps. In other words, a cusp, which is a concept in the device-independent color space, is specified by color data in the device-dependent color space, and each of a plurality of cusps included in the cusp row having the highest saturation for each hue is mapped to the device-independent color space. Therefore, it is possible to easily obtain a cusp string of hues mapped in the device-independent color space.

  Preferably, the first color space is a color space in which a color gamut outline of the device includes an origin of an orthogonal coordinate system indicating the color space. In other words, the cusp can be easily acquired in the first color space.

  Preferably, the first color space is a device-dependent color space, and the second color space is a device-independent color space. That is, a cusp can be easily obtained even for a device having a non-linear color gamut contour in a device-independent color space.

A second feature of the present invention is color data processing for mapping color data representing an image in a color gamut of a device-dependent color space to color data representing an image in a color gamut of a device-independent space. In the method, a plurality of cusps having the highest saturation for each hue in the device-independent color space are identified in the device-dependent color space from the device gamut outline in the device-dependent color space, and the plurality A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space, and mapping the identified cusp rows to the device-independent color space , Interpolating between each of the cusps included in the cusp sequence mapped to the device-independent color space, and based on the interpolated result, The color data representing an image in the color gamut of the device-dependent color space and the color data processing method for mapping color data representing an image color gamut of the device-independent color space. Therefore, since a cusp string for each hue in the device-independent color space can be easily obtained, the amount of calculation required for formula mapping based on the cusp string can be reduced.

Preferably, for each of a plurality of cusps included in the cusp sequence mapped in the device-independent color space, a one-dimensional lookup table indicating color data for a hue angle in the device-independent color space is created. By interpolating between each of the plurality of cusps included in the mapped cusp row . That is, it is possible to easily interpolate the color data for the hue angle even for a hue that is not mapped in the device-independent color space.

Preferably, a one-dimensional lookup table indicating the lightness with respect to the hue angle in the device-independent color space is created for each of a plurality of cusps included in the cusp sequence mapped in the device-independent color space. Thus, the lightness with respect to the hue angle between each of the plurality of cusps included in the mapped cusp row is interpolated. That is, it is possible to easily interpolate the color data for the hue angle even for a hue that is not mapped in the device-independent color space.

According to a third feature of the present invention, in a color data processing system for mapping color data in a device-dependent color space to a device-independent space, the device non-color is determined from the device color data in the device-dependent color space. A plurality of cusps having the highest saturation for each hue in the dependency space are specified in the device-dependent color space, and the specified plurality of cusps other than the vertexes of the device color gamut outline in the device-dependent color space A cusp string specifying means for specifying a plurality of cusps including a cusp as a cusp string, a mapping means for mapping the cusp string specified by the cusp string specifying means to the device independent color space, and the device independent color space Interpolation means for interpolating between each of a plurality of cusps included in the cusp sequence mapped to In color data processing system to.

  Preferably, the first color space is a color space in which a color gamut outline of the device includes an origin of an orthogonal coordinate system indicating the color space.

According to a fourth feature of the present invention, in the color data processing system for mapping the color data of the device-dependent color space to the device-independent space, the device non-color is determined from the device color data in the device-dependent color space. A plurality of cusps having the highest saturation for each hue in the dependency space are specified in the device-dependent color space, and the specified plurality of cusps other than the vertexes of the device color gamut outline in the device-dependent color space A cusp string specifying means for specifying a plurality of cusps including a cusp as a cusp string, a mapping means for mapping the cusp string specified by the cusp string specifying means to the device independent color space, and the device independent color space Interpolating means for interpolating between each of the cusps included in the cusp sequence mapped to Based on the results of the between the color data representing an image in the color gamut of the device-dependent color space and the color data processing system for mapping color data representing an image color gamut of the device-independent color space.

Preferably, the interpolation unit creates a one-dimensional lookup table indicating color data for a hue angle in the device-independent color space for each of a plurality of cusps included in the cusp sequence mapped by the mapping unit. And a table creating means for interpolating between each of the plurality of cusps included in the cusp sequence mapped by the mapping means based on the one-dimensional lookup table created by the table creating means.

Preferably, the interpolation means includes a one-dimensional look-up table indicating brightness with respect to a hue angle in the device-independent color space for each of a plurality of cusps included in the cusp sequence mapped by the mapping means. A table creating unit for creating, and based on a one-dimensional lookup table created by the table creating unit, interpolates lightness with respect to hue angles between a plurality of cusps included in the cusp sequence mapped by the mapping unit. .

According to a fifth feature of the present invention, in the color data processing program for processing color data using a computer so as to map the color data of the device-dependent color space to the device-independent color space, the device A plurality of cusps having the highest saturation for each hue in the device-independent color space are identified in the device-dependent color space from the device color data in the dependent color space, and the plurality of identified cusps are: Identifying a plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space as a cusp sequence, mapping the identified cusp sequence to the device-independent color space, and the device Interpolating between each of the cusps included in the cusp sequence mapped to the independent space. In color data processing program executed by a computer.

According to a sixth feature of the present invention, in the color data processing program for processing color data using a computer so as to map the color data of the device-dependent color space to the device-independent color space, the device A plurality of cusps having the highest saturation for each hue in the device-independent color space are identified in the device-dependent color space from the device color data in the dependent color space, and the plurality of identified cusps are: Identifying a plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space as a cusp sequence, mapping the identified cusp sequence to the device-independent color space, and the device Interpolating between each of a plurality of cusps included in a cusp sequence mapped to an independent space; And causing the computer to execute a step of mapping color data representing an image in the color gamut of the first device to color data representing an image in the color gamut of the second device based on the result obtained In the data processing program.

According to a seventh aspect of the present invention, there is provided a storage in which a color data processing program for processing color data using a computer is recorded so that the color data in the device-dependent color space is mapped to the device-independent color space. In the medium, a plurality of cusps having the highest saturation for each hue in the device-independent color space are specified in the device-dependent color space from the device color data in the device-dependent color space, and the plurality of specified A plurality of cusps including a cusp other than the vertices of the device color gamut outline in the device-dependent color space, and mapping the identified cusp sequence to the device-independent color space Between each step and a plurality of cusps included in the cusp sequence mapped to the device-independent space. There the steps on a computer-readable recording medium recording a color data processing program to be executed by a computer for.

According to an eighth aspect of the present invention, a memory in which a color data processing program for processing color data using a computer is recorded so as to map the color data of the device-dependent color space to the device-independent color space. In the medium, a plurality of cusps having the highest saturation for each hue in the device-independent color space are specified in the device-dependent color space from the device color data in the device-dependent color space, and the plurality of specified A plurality of cusps including a cusp other than the vertices of the device color gamut outline in the device-dependent color space, and mapping the identified cusp sequence to the device-independent color space Between each step and a plurality of cusps included in the cusp sequence mapped to the device-independent space. And a step of mapping color data representing an image in the color gamut of the first device to color data representing an image in the color gamut of the second device based on the interpolated result And a computer-readable recording medium on which a color data processing program to be executed is recorded.

  According to the present invention, it is possible to easily obtain a cusp having the highest saturation for each hue in a predetermined color space.

Next, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of a color data processing system 1 according to an embodiment of the present invention. The color data processing system 1 is configured, for example, by connecting a control device 2 to an image output unit 4 via a network 3 and has, for example, full-color image processing and image forming functions. The image output unit 4 includes a plurality of image output devices, and includes, for example, printing devices 40-1 and 40-2 and a display device 42. The printing devices 40-1 and 40-2 print color images according to color data of Y (yellow), M (magenta), C (cyan), and K (black), respectively, under the control of the control device 2. The display device 42 displays a color image according to color data of R (red), G (green), and B (blue purple) each having, for example, 8-bit gradation under the control of the control device 2. Note that the printing devices 40-1 and 40-2 and the display device 42 have different color gamuts (color gamuts).

In FIG. 2, the structure of the control apparatus 2 is shown.
The control device 2 is, for example, a PC (Personal Computer) or the like, and includes an input unit 20, a display unit 22, a storage unit 24, a communication unit 26, and a control device main body 28. For example, the control device 2 includes a recording medium 240 such as a CD-ROM. The image output unit 4 is controlled by operating the supplied software. The input unit 20 includes input devices such as a keyboard and a mouse, and accepts user instructions to the color data processing system 1. The display unit 22 is a CRT display device or an LCD display device, and displays the processing result in the control device 2 and a signal received from the image output unit 4. The display unit 22 and the display device 42 have different color gamuts.

  The storage unit 24 is a program for controlling each unit constituting the color data processing system 1, a database such as profiles of the display unit 22 and the image output unit 4, settings for the color data processing system 1, and data created by the control device 2. Memorize etc. The communication unit 26 connects the image output unit 4 and the control device main body 28 via the network 3. The control device main body 28 includes a CPU 280 and a memory 282, and controls each part constituting the control device 2.

Next, an example of a color data processing program executed by the control device 2 will be described.
FIG. 3 is a program configuration diagram showing the configuration of the color data processing program 5 executed by the control device 2.
4 and 5 are graphs showing cusp information (coordinates) on the color space in the color data processing program 5. FIG.
As shown in FIG. 3, the color data processing program 5 includes, for example, a color gamut outline specifying unit 50, a mapping unit 52, an interpolation unit 54, and a color gamut mapping unit 56, and is device independent of the first device (mapping source). The color data is mapped to device-independent color data that can be reproduced by the second device (mapping destination).
Hereinafter, a case where the printing apparatus 40-1 is the first device, the display apparatus 42 is the second device, and the control apparatus 2 maps the color gamut of the printing apparatus 40-1 to the color gamut of the display apparatus 42 will be described as an example. .

The color gamut outline specifying unit 50 includes a vertex creation unit 500, a polygon (polygon) creation unit 502, and a cusp sequence (maximum saturation point sequence) acquisition unit 504. The vertex creation unit 500 creates vertices for the polygon creation unit 502 to create a polygon (for example, a triangle) on the color gamut outline in the RGB color space of the display device 42 in order to specify the color gamut of the second device, for example. To do.
As shown in FIG. 4A, in the RGB color space, the color gamut outline of the display device 42 is a cube including the origin. For example, the vertex creation unit 500 creates each of the lattice points obtained by dividing the surface of the cube showing the color gamut outline of the display device 42 into a lattice shape at an arbitrary interval as the vertex (color data) for the polygon.

  The polygon creation unit 502 creates a plurality of triangles so that each vertex created by the vertex creation unit 500 is a vertex of a polygon. That is, the polygon creation unit 502 specifies the color gamut outline in the RGB color space of the display device 42 as a set of a plurality of triangles (defined by three vertices).

  The cusp string acquisition unit 504 acquires, as a cusp string, a column of vertices that are the vertices of a plurality of triangles created by the polygon creation unit 502 and have the highest saturation for each hue in the RGB color space. In the present invention, cusps (cusps) are color data that are the highest saturation points (for each hue) with respect to the hue angle in the color space. Therefore, in the RGB color space, each cusp is arranged in a row on the vertices and sides of a cube indicating the color gamut outline and is easily obtained.

  As described above, the color gamut outline specifying unit 50 creates a plurality of polygons on the color gamut outline in the RGB color space of the display device 42, acquires a cusp row, and obtains a plurality of polygons (vertices of polygons including the cusp row). The color gamut outline of the display device 42 is specified by the group) and output to the mapping unit 52. That is, the amount of calculation for specifying the color gamut outline is adjusted by adjusting the lattice spacing of the cube surface indicating the color gamut outline.

The mapping unit 52 (FIG. 3) displays a plurality of polygons (a vertex group of polygons including a cusp row) in the RGB color space received from the color gamut outline specifying unit 50, for example, the device-independent color shown in FIG. The image is mapped onto the CIELAB color space (CIE L ^* a ^* b ^* color system), which is a space, and the mapped cusp sequence is output to the interpolating unit 54, and a plurality of mapped polygons (polygons including the cusp sequence) are output. (Vertex group) is output to the color gamut mapping unit 56. As shown in FIG. 5, the cusp mapped by the mapping unit 52 is on the intersection of the color gamut outline of the polygon and the half plane (L ^* -C ^* plane) including the L ^* axis and the target point of the predetermined hue. This is the color data of the highest saturation point.
The mapping unit 52 may map a plurality of polygons by converting the color data in the RGB color space into the XYZ color space using the conversion matrix and then converting the color data into the CIELAB color space. May be used to convert color data. The mapping unit 52 may map a plurality of polygons by conversion using a so-called color conversion (prediction) model such as a neural network and a regression model.

The interpolation unit 54 (FIG. 3) includes a one-dimensional lookup table (LUT) creation unit 540, and uses the one-dimensional lookup table 6 created by the LUT creation unit 540 between each cusp received from the mapping unit 52. And output to the color gamut mapping unit 56.
FIG. 6 is a chart illustrating the one-dimensional lookup table 6 created by the LUT creation unit 540.
As shown in FIG. 6, the LUT creation unit 540 is a one-dimensional unit that receives the hue angle (rad) and outputs the value of L ^* a ^* b ^* for each cusp shown in FIG. 4B, for example. A lookup table 6 is created. In the one-dimensional lookup table 6, for example, the cusp P1 having the maximum hue angle of −π or less is set as the first cusp (start cusp), and the cusp P2 having the minimum hue angle of π or more is set as the last cusp (end cusp). As a result, the values of L ^* a ^* b ^* for each cusp are arranged in order of increasing hue angle. In this way, in the one-dimensional lookup table 6, for example, two cusps (P1, P2) are arranged twice with different hue angles, and the range of the cusp hue angles shown in the one-dimensional lookup table 6 is 2π or more. It has become.

Therefore, the interpolation unit 54 linearly interpolates between the cusps arranged in the one-dimensional lookup table 6, for example, so that the cusp L ^* a ^* b ^* with respect to an arbitrary hue angle θ (−π ≦ θ <π) is satisfied. The value can be calculated. For example, a hue angle in the CIELAB color space is calculated for predetermined color data, a section between cusps including the calculated hue angle is specified using the one-dimensional lookup table 6, and by linear interpolation by using the cusp of L ^* a ^* b ^* values at the ends, it is possible to calculate the cusp of L ^* a ^* b ^* values for hue angle of a predetermined color data.

The gamut mapping unit 56 (FIG. 3) receives a plurality of polygons (polygon vertices including a cusp row) from the mapping unit 52, receives a cusp interpolation result from the interpolation unit 54, and receives the first device ( The device-independent color data of the printing device 40-1) is mapped to device-independent color data that can be reproduced by the second device (display device 42) and output. For example, the color gamut mapping unit 56 calculates a hue angle for the color data in the device-independent color gamut of the first device, and the value of the cusp L ^* a ^* b ^* with respect to the calculated hue angle is calculated by the interpolation unit 54. A color in the device-independent color gamut of the first device with a point on the L * axis (a ^* and b ^* = 0) having the brightness of the calculated cusp as the target point (reference point) calculated according to the interpolation result The data is mapped to color data in a device-independent color gamut that can be reproduced by the second device and output.

FIG. 7 shows a process (S10) for mapping the device-independent color data of the first device to the device-independent color data of the second device by the control device 2 executing the color data processing program 5. .
As shown in FIG. 7, in step 100 (S100), the vertex creation unit 500 of the color gamut outline specifying unit 50 identifies the device-dependent color gamut outline of the second device (display device 42). The polygon creation unit 502 creates vertices for creating a polygon on the color gamut outline in the RGB color space.

  In step 102 (S102), the polygon creation unit 502 creates a plurality of triangles so that each vertex created by the vertex creation unit 500 becomes a vertex of the polygon, and specifies the color gamut outline in the RGB color space of the display device 42. To do.

  In step 104 (S104), the cusp string acquisition unit 504 acquires, as a cusp string, a column of vertices that are the vertices of a plurality of triangles created by the polygon creation unit 502 and have the highest saturation for each hue in the RGB color space. To do.

  In step 106 (S106), the mapping unit 52 maps a plurality of polygons (vertex group of polygons including cusp columns) in the RGB color space received from the color gamut outline specifying unit 50 onto the CIELAB color space. In addition to outputting to the interpolation unit 54, a plurality of polygons are output to the color gamut mapping unit 56.

  In step 108 (S108), the LUT creation unit 540 of the interpolation unit 54 creates the one-dimensional lookup table 6 from the cusp sequence received from the mapping unit 52.

  In step 110 (S110), the interpolation unit 54 interpolates between the cusps received from the mapping unit 52 using the one-dimensional look-up table 6, and thereby the device-independent color data of the input first device. The cusp corresponding to the hue angle it has is calculated and output to the gamut mapping unit 56.

In step 112 (S112), the color gamut mapping unit 56 receives a plurality of polygons (vertex group of polygons including a cusp sequence) from the mapping unit 52, receives a cusp interpolation result from the interpolation unit 54, and is input. The device-independent color data of one device is mapped to the device-independent color data that can be reproduced by the second device using points on the L ^* axis having cusp brightness, and output.

  The device-independent color data of the first device is generated when the control device 2 converts the device-dependent color data of the first device using a profile. Further, the control device 2 converts device-independent color data that can be reproduced by the second device into device-dependent color data of the second device using a profile.

As described above, the color data processing system 1 can easily calculate the L ^* a ^* b ^* value of the cusp with respect to an arbitrary hue angle by using the one-dimensional lookup table 6, for example, the brightness of the cusp. By using the points on the L ^* axis having, the color gamut mapping between a plurality of devices having different color gamuts can be performed at high speed while preventing the reversal of saturation.
In the above-described embodiment, the example in which the color data processing program 5 specifies the color gamut of the second device has been described. However, the color data processing program 5 is not limited to this, and the color data processing program 5 has the color gamut of the first device. Alternatively, it may be specified and mapping may be performed between the specified color gamuts.

Next, a modified example of the color data processing program 5 will be described.
FIG. 8 is a graph showing processing according to a modification of the color data processing program 5, wherein (A) is a graph showing the color gamut outline and cusp of the display device 42 in the RGB color space, and (B) is CIELAB color. It is a graph which shows the cusp mapped on space.
In the modification of the color data processing program 5, the vertex creation unit 500 creates a cube vertex indicating the color gamut outline of the second device (display device 42) as a vertex (color data) for the polygon.

  The polygon creation unit 502 creates six squares so that each vertex created by the vertex creation unit 500 is a vertex of a polygon (polygon). That is, the polygon creation unit 502 identifies the color gamut outline in the RGB color space of the display device 42 as a set of six squares (defined by four vertices).

  The cusp string acquisition unit 504 acquires, as a cusp string, a sequence of arbitrary points that are the vertices or points on the sides of the six squares created by the polygon creation unit 502 and have the highest saturation for each hue in the RGB color space. To do.

  In this way, the color gamut outline specifying unit 50 creates six squares that are color gamut outlines in the RGB color space of the display device 42, acquires cusp rows, and is a cube surface that is the color gamut outline in the RGB color space. The color gamut outline of the display device 42 is specified by the upper arbitrary point (not shown) and the cusp row, and is output to the mapping unit 52.

  The mapping unit 52 converts a cusp string in the RGB color space received from the color gamut outline specifying unit 50 and an arbitrary point (not shown) on the surface of the cube that is the color gamut outline in the RGB color space, as shown in FIG. Are mapped onto the CIELAB color space, which is a device-independent color space, and the mapped cusp sequence is output to the interpolation unit 54, and the mapped arbitrary points and cusp sequences are output to the gamut mapping unit 56. Output.

The interpolating unit 54 interpolates between the cusps received from the mapping unit 52 using the one-dimensional lookup table 6 created by the LUT creating unit 540, so that the device-independent color data of the first device input is input. The cusp corresponding to the hue angle it has is calculated and output to the gamut mapping unit 56.
The color gamut mapping unit 56 receives the mapped arbitrary point and cusp sequence from the mapping unit 52, receives the cusp interpolation result from the interpolation unit 54, and receives the input device-independent color data of the first device as the second. Output by mapping to device-independent color data that can be reproduced by the device.

When only the L ^* a ^* b ^* value of the cusp of the second device having the same hue angle is calculated for arbitrary color data in the CIELAB color space, the color gamut contour in the RGB color space is calculated. CIELAB color space is a cusp string consisting only of cusps that are points on the top or sides of six squares (identical to the color gamut outline) and that have the highest saturation for each hue in the RGB color space. It is also possible to create a one-dimensional lookup table 6 and interpolate between cusps in the CIELAB color space.

  In the above embodiment, the case where the color gamut in the RGB color space of the device is specified by a plurality of polygons has been described as an example. However, the present invention is not limited to this, and the present invention is not limited to this. The present invention can also be applied to a device that outputs magenta), Y (yellow), a device that outputs C, M, Y, K (black), or a device that outputs four or more colors. A device that outputs CMYK has the same cusp as a device that outputs CMY because K does not affect the cusp. Further, even if a device that outputs four or more colors is a device that can output C, P (purple), M, and Y as primary colors, for example, C100%, C100% and P100%, P100%, P100% Also, cusp rows can be easily created in the order of M100%, M100%, M100% and Y100%, Y100%, Y100% and C100%, and the present invention can be applied.

It is a block diagram which shows the outline | summary of the color data processing system which concerns on embodiment of this invention. It is a block diagram which shows the structure of a control apparatus. It is a program block diagram which shows the structure of the color data processing program performed with a control apparatus. FIG. 6 is a graph showing processing by a color data processing program, in which (A) is a graph showing the color gamut outline and cusp of the display device in the RGB color space, and (B) is a color gamut outline mapped on the CIELAB color space; It is a graph which shows a cusp. It is a graph which shows the information (coordinate) of the cusp on a L ^* -C ^* plane. 6 is a chart illustrating a one-dimensional lookup table created by an LUT creation unit. It is a flowchart which shows the process (S10) which maps the device independent color data of a 1st device to the device independent color data of a 2nd device, when a control apparatus runs a color data processing program. 7 is a graph showing processing according to a modification of the color data processing program, where (A) is a graph showing the color gamut outline and cusps of the display device in the RGB color space, and (B) is a cusp mapped on the CIELAB color space. It is a graph which shows.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Color data processing system 2 ... Control apparatus 22 ... Display part 24 ... Storage part 240 ... Recording medium 28 ... Control apparatus main body 4 ... Image output part 40-1, 40-2 ... Printing device 42 ... Display device 5 ... Color data processing program 50 ... Color gamut outline identification unit 500 ... Vertex creation unit 502 ... Polygon creation unit 504 ... Cusp Column acquisition unit 52 ... Mapping unit 54 ... Interpolation unit 540 ... LUT creation unit 56 ... Color gamut mapping unit 6 ... One-dimensional lookup table

Claims (14)

In a color data processing method for mapping color data of a device-dependent color space to a device-independent color space,
From the device color data in said device dependent color space, a plurality of cusp with the highest saturation of each hue in the device independent color space as well as specified in the device dependent color space, a a plurality of cusp that is the specific A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space ,
Mapping the identified cusp string to the device independent color space;
A color data processing method for interpolating between a plurality of cusps included in a cusp string mapped to the device-independent color space. The color data processing method according to claim 1, wherein the device-dependent color space is a color space in which a color gamut outline of the device includes an origin of an orthogonal coordinate system indicating the color space. In a color data processing method for mapping color data representing an image in a color gamut of a device-dependent color space to color data representing an image in a color gamut of a device-independent space,
From color gamut boundary of a device in the device dependent color space, a plurality of cusp with the highest saturation of each hue in the device independent color space as well as specified in the device dependent color space, a plurality of cusp that is the specific A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space are identified as cusp rows,
Mapping the identified cusp string to the device independent color space;
Interpolating between each of a plurality of cusps included in a cusp string mapped to the device-independent color space;
A color data processing method for mapping color data representing an image in the color gamut of the device-dependent color space to color data representing an image in the color gamut of the device-independent color space based on the interpolated result. For each of a plurality of cusps included in the cusp sequence mapped to the device-independent color space, mapping is performed by creating a one-dimensional lookup table indicating color data for a hue angle in the device-independent color space. The color data processing method according to claim 3, wherein interpolation is performed between each of the plurality of cusps included in the cusp row. For each of a plurality of cusps included in the cusp sequence mapped to the device-independent color space, a mapped cusp is created by creating a one-dimensional lookup table indicating the brightness with respect to the hue angle in the device-independent color space. The color data processing method according to claim 3, wherein interpolation is performed using lightness with respect to hue angles of a plurality of cusps included in a column. In a color data processing system that maps device-dependent color space color data to device-independent space,
A plurality of cusps having the highest saturation for each hue in the device-independent space are identified in the device-dependent color space from the device color data in the device-dependent color space, and the plurality of identified cusps are Cusp string specifying means for specifying a plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space as cusp strings;
Mapping means for mapping the cusp string specified by the cusp string specifying means to the device-independent color space;
Interpolating means for interpolating between each of a plurality of cusps included in a cusp sequence mapped to the device-independent color space.   The color data processing system according to claim 6, wherein the device-dependent color space is a color space in which a color gamut outline of the device includes an origin of an orthogonal coordinate system indicating the color space. In a color data processing system that maps device-dependent color space color data to device-independent space,
A plurality of cusps having the highest saturation for each hue in the device-independent space are identified in the device-dependent color space from the device color data in the device-dependent color space, and the plurality of identified cusps are Cusp string specifying means for specifying a plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space as cusp strings;
Mapping means for mapping the cusp string specified by the cusp string specifying means to the device-independent color space;
Interpolating means for interpolating between each of a plurality of cusps included in a cusp sequence mapped to the device-independent color space;
Color data processing for mapping color data representing an image in the color gamut of the device-dependent color space to color data representing an image in the color gamut of the device-independent color space based on the result of interpolation by the interpolation means system. The interpolation means creates a table creation means for creating a one-dimensional lookup table indicating color data for a hue angle in the device-independent color space for each of a plurality of cusps included in the cusp sequence mapped by the mapping means. The color data processing system according to claim 8, further comprising: interpolating between each of a plurality of cusps included in the cusp sequence mapped by the mapping unit based on a one-dimensional lookup table created by the table creation unit. The interpolating means comprises table creating means for creating a one-dimensional lookup table indicating the lightness with respect to the hue angle in the device-independent color space for each of a plurality of cusps included in the cusp sequence mapped by the mapping means. And interpolating using brightness values for hue angles of a plurality of cusps included in the cusp sequence mapped by the mapping unit based on the one-dimensional lookup table created by the table creation unit. Color data processing system. In a color data processing program for processing color data using a computer so as to map the color data of the device-dependent color space to the device-independent color space,
From the device color data in said device dependent color space, a plurality of cusp with the highest saturation of each hue in the device independent color space as well as specified in the device dependent color space, a a plurality of cusp that is the specific A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space ,
Mapping the identified cusp string to the device independent color space;
A color data processing program that causes a computer to execute a step of interpolating between each of a plurality of cusps included in a cusp string mapped to the device-independent space. In a color data processing program for processing color data using a computer so as to map the color data of the device-dependent color space to the device-independent color space,
From the device color data in said device dependent color space, a plurality of cusp with the highest saturation of each hue in the device independent color space as well as specified in the device dependent color space, a a plurality of cusp that is the specific A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space ,
Mapping the identified cusp string to the device independent color space;
Interpolating between each of a plurality of cusps included in a cusp sequence mapped to the device-independent space;
Mapping the color data representing the image in the color gamut of the first device to the color data representing the image in the color gamut of the second device based on the interpolated result. Data processing program. In a storage medium recording a color data processing program for processing color data using a computer so as to map the color data of the device-dependent color space to the device-independent color space,
From the device color data in said device dependent color space, a plurality of cusp with the highest saturation of each hue in the device independent color space as well as specified in the device dependent color space, a a plurality of cusp that is the specific A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space ,
Mapping the identified cusp string to the device independent color space;
A computer-readable recording medium having recorded thereon a color data processing program for causing a computer to execute interpolation between a plurality of cusps included in a cusp string mapped to the device-independent space. In a storage medium recording a color data processing program for processing color data using a computer so as to map the color data of the device-dependent color space to the device-independent color space,
From the device color data in said device dependent color space, a plurality of cusp with the highest saturation of each hue in the device independent color space as well as specified in the device dependent color space, a a plurality of cusp that is the specific A plurality of cusps including cusps other than the vertices of the device color gamut outline in the device-dependent color space ,
Mapping the identified cusp string to the device independent color space;
Interpolating between each of a plurality of cusps included in a cusp sequence mapped to the device-independent space;
Mapping the color data representing the image in the color gamut of the first device to the color data representing the image in the color gamut of the second device based on the interpolated result. A computer-readable recording medium on which a data processing program is recorded.

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