JP2006180063A - Color processing method and color processing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to more easily grasp a stereoscopic shape indicating color gamuts of a plurality of color data. <P>SOLUTION: This method has a color data acquiring process of acquiring a plurality of color data; stereoscopic shape generating process of generating a stereoscopic shape of the color gamuts of the plurality of acquired color data; line of sight setting process of setting a visual point position and a direction of line of sight; pseudo three-dimensional display process of pseudo-three-dimensionally displaying the generated stereoscopic shape; cross sectional surface setting process of setting the position of a cross sectional surface perpendicularly to the direction of line of sight, on the basis of an instruction of the user; and cross sectional surface processing process of preventing one side of the stereoscopic shape from being displayed at a boundary in which the set cross sectional surface crosses the generated stereoscopic shape. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a display that displays a three-dimensional shape indicating a color gamut in a pseudo three-dimensional manner.

  With the widespread use of personal computers and workstations, desktop publishing (DTP) has become commonly used. Under such circumstances, an image displayed on a monitor is increasingly reproduced by a printer. At this time, it is desirable that the color image on the monitor matches the output image of the printer.

  However, it is difficult to completely reproduce the image on the monitor with a printer. One reason is that the color reproduction range differs between the monitor and the printer.

  A gamut mapping (color space compression) technique has been proposed as a color process for coping with the difference in the color reproduction range between the monitor and the printer.

  Conventionally, various gamut mapping techniques have been developed. However, as gamut mapping techniques have developed, a method for analyzing / evaluating gamut mapping has been desired.

  Japanese Patent Application Laid-Open No. 2004-228561 describes a method for performing gamut mapping analysis / evaluation by displaying a color reproduction range of a printer together with an image in a pseudo three-dimensional display on a color space.

On the other hand, there are processes performed on the color space other than gamut mapping. For example, the achromatic color axis of the color reproduction range obtained by color measurement may be shifted from the L axis. For this reason, a method of performing achromatic color axis correction that matches the achromatic color axis with the L axis has been proposed. Further, in the L ^* u ^* v ^* color space, a shift may occur in the hue direction when performing gamut mapping. For this reason, a method of correcting in the hue direction so as to compensate for the deviation in the hue direction has been proposed.

Regarding color adjustment techniques other than gamut mapping, a technique for performing analysis / evaluation is desired, but a technique for performing analysis / evaluation of color adjustment has not been proposed.
JP 2003-173437 A

  Japanese Patent Application Laid-Open No. 2004-228561 describes a method of displaying / displaying a color distribution indicating a color reproduction range of a printer and analyzing / evaluating gamut mapping.

  However, in order to efficiently perform the analysis / evaluation of the gamut mapping and the color adjustment described above, the technology disclosed in Patent Document 1 has insufficient information to be presented, and further reduces the burden on the developer in the development of the gamut mapping. New technology is needed.

  An object of the present invention is to make it easy to grasp a three-dimensional shape on a color space indicating a color gamut of a plurality of color data.

  Another object of the present invention is to make it easier to grasp the relationship in the color space between the solid shape indicating the color gamut of the first plurality of color data and the color distribution indicating the second plurality of color data.

  According to the first aspect of the present invention, a color data acquisition step of acquiring a plurality of color data, a solid shape generation step of generating a solid shape of a color gamut of the acquired plurality of color data, and a viewpoint position and a line-of-sight direction are set A line-of-sight setting step, a pseudo-three-dimensional display step of displaying the generated three-dimensional shape in a pseudo-three-dimensional manner, and a ring-cut surface setting step of setting a position of the ring-cut surface perpendicular to the line-of-sight direction based on a user instruction And a cut surface processing step in which one side of the three-dimensional shape is not displayed on the boundary of the surface where the set circular surface and the generated three-dimensional shape intersect.

  The invention according to claim 8 is a color data acquisition step for acquiring at least a first plurality of color data and a second plurality of color data, and generates a three-dimensional shape indicating a color gamut of the first plurality of color data. The ratio of the number of color data included in the three-dimensional shape and the number of color data not included in the three-dimensional shape in the three-dimensional shape generation step to be performed and the color distribution on the color space indicated by the second plurality of color data It is characterized by having an inside / outside ratio display step for displaying.

  According to the first aspect of the present invention, it is possible to easily grasp a three-dimensional shape indicating a color gamut of a plurality of color data.

  According to the seventh aspect of the present invention, the relationship in the color space on the color space between the solid shape indicating the color gamut of the first plurality of color data and the color distribution indicating the second plurality of color data is further grasped. It can be made easier.

In this embodiment, the color space to be used is L ^* a ^* b ^* . However, other color spaces such as L ^* u ^* v ^* can be used.

  In this embodiment, the object indicates a target to be displayed such as a device color reproduction range or an image color distribution.

  The object is displayed in a pseudo three-dimensional manner using a point group, a wire frame, or a solid (polyhedron) composed of a plurality of color data. However, a solid shape such as a sphere may be used in addition to the solid.

  FIG. 5 shows an example of processing result display in the present embodiment. The color distribution of the image is displayed as a point group (501), the color reproduction range of the input device as a wire frame (502), and the color reproduction range of the output device as a solid (503).

  When a plurality of objects are displayed together, the positional relationship between the objects can be grasped more visually.

  In FIG. 5, the image (504) is also displayed together with the color distribution (501) of the image.

(Configuration of object display system)
FIG. 1 is a diagram showing the configuration of a system in the present embodiment. 101 is a color monitor, 102 is an operation unit, 103 is a monitor I / F, 104 is a CPU, 105 is an operation unit I / F, 106 is a RAM, and 107 is an HDD that stores programs and data for performing various processes. It is.

  First, a user instruction is input from the operation unit 102. This instruction is transmitted as an instruction to the CPU 104 via the operation unit I / F 105. The CPU 104 loads a program and data for realizing processing described below from the HDD 107 into the RAM 106. The CPU 104 performs various processes on the data on the RAM 106 according to the loaded program, and displays the result on the color monitor 101 via the monitor I / F 103.

(Processing flow for object display)
FIG. 2 shows the flow of processing for displaying an object in this embodiment.

  After starting the system (S201), in S202, initial values for the viewpoint and the line-of-sight direction are set.

  The object in this embodiment is a three-dimensional solid. Therefore, in order to display a three-dimensional object on a two-dimensional plane in a pseudo three-dimensional manner, it is necessary to set a viewpoint and a line-of-sight direction.

  As the viewpoint and the line-of-sight direction, arbitrary points on a color space set in advance by the user are used.

  In S203, color data of an object to be displayed is input based on a user instruction.

  When displaying the color reproduction range of the device as an object, a file storing colorimetric values indicating the range that can be output by the output device is specified using a UI as shown in FIG. 3B (307). ).

  For the colorimetric values, a plurality of color data indicating the surface of the color reproduction range or a plurality of color data indicating the color reproduction range including the internal area is used.

  For example, R (red), G (green), B (blue), C (cyan), M (magenta), Y (yellow), K (black), W (white) indicating the surface of the device color reproduction range. If a file storing each color coordinate value is input, the color reproduction range of the device can be displayed in a dodecahedron.

  On the other hand, when displaying the color distribution of an image as an object, an image file storing color coordinate values is specified using a UI as shown in FIG. 3A (301).

  The image file stores a plurality of color data indicating an image before or after color space compression.

In this embodiment, an object is displayed on the L ^* a ^* b ^* space. Therefore, the color coordinate value indicated by RGB or CMYK data stored in the file is converted to the color coordinate value indicated by L ^* a ^* b ^* data. Therefore, an ICC profile is used in this embodiment. The ICC profile follows the format defined by the ICC (International Color Consortium), for example, the correspondence between device-dependent color data such as RGB and CMYK and device-independent color data such as L ^* a ^* b ^*. It represents. An ICC profile for CMYK is designated in 302-1, an ICC profile for RGB is designated in 302-2, and an ICC profile for Spot is designated in 302-3.

A conversion process using an ICC profile will be described with reference to FIG. First, point sequence data for each pixel of RGB or CMYK is extracted from the selected image file. The extracted RGB or CMYK point sequence data is converted into L ^* a ^* b ^* data by the color matching module using the selected ICC profile.

After the conversion, the object processing described later is performed on the L ^* a ^* b ^* data, and for example, a point cloud object indicating image data as shown in FIG. 4B is displayed.

  If a file storing color coordinate values of an image after gamut mapping is selected at 301, the color distribution of the image after gamut mapping can be confirmed.

  In step S204, an object display method is selected using a UI 308 shown in FIG.

  In this embodiment, point clouds, wire frames, and solids are prepared as object display methods.

  In this embodiment, a plurality of objects can be displayed together. If there is an object to be displayed in addition to the objects for which the setting from S202 to S204 has already been performed (S205), the processing from S202 to S204 is performed again.

  In S206, object processing is performed. The object process is a process for displaying an object in accordance with information set between S202 and S204.

When the object is the color distribution of the image and the point cloud display is performed, the method shown in FIG. 4 is used to convert the image data into L ^* a ^* b ^* color coordinate values, and in the L ^* a ^* b ^* space. Plot to. If the number of pixels of the image data is large, the calculation load may be reduced by performing a thinning process and reducing the number of pixels.

  In addition, when a plurality of color data indicates the surface of the color reproduction range and the point cloud display is selected by the user, the point cloud is generated with a uniform density within the color reproduction range.

If the selected display method is not a point cloud but a wire frame or a solid, a Convex Hull is created from a L ^* a ^* b ^* color coordinate value group using a known method, and an L ^* a ^* b ^* space is created. Create a polyhedron on top. Convex hull is the smallest convex polyhedron that contains all the given point sets inside.

  When the display method is a wire frame, the wire frame is generated by connecting the feature points on the generated polyhedron.

  On the other hand, when the display method is a solid, the solid is generated using each plane constituting the polyhedron.

  Next, the color coordinate value of each object is coordinate-converted from three-dimensional coordinates to two-dimensional coordinates according to the viewpoint and line-of-sight direction set in S203.

  Then, the color coordinate value of each object subjected to coordinate conversion is displayed on a display device such as a monitor in a pseudo three-dimensional manner.

  Pseudo three-dimensional display means displaying an object represented by three-dimensional coordinates on a monitor plane that is a two-dimensional plane. After the object is displayed, the state waits for input (S207).

  In S207, when a user operation is performed, if the operation is a viewpoint changing operation (S208), the process proceeds to S208, and the viewpoint changing operation is performed. Then, each object is reprocessed according to the changed viewpoint. When the object is reprocessed, the above-described coordinate conversion from the three-dimensional coordinates to the two-dimensional coordinates is performed again. Thereafter, the state waits for input (S207).

  Further, when the operation is the position / display setting of the cut surface, the process proceeds to S209 and the position / display setting of the cut surface is performed. Here, the cut surface is a plane arranged in a color space such as 304 or 305 in FIG. In the case of using a circular cut surface, the user turns on a check box of “display cut surface” in the UI of 306-1.

  As shown in FIG. 3D, the circular cut surface (304 or 305) is set at a position perpendicular to the viewing direction. The solid cross section that intersects with the set cross section is not displayed, but the cross section displays the interior of the solid.

  In the present embodiment, as shown in FIG. 3, two surfaces of a ring cutting surface 1 (304) and a ring cutting surface 2 (305) are arranged. With respect to the line-of-sight direction, the ring-cut surface 1 (304) is on the near side, and the ring-cut surface 2 (305) is on the back side. The near side of the solid with respect to the cut surface 1 and the back side of the solid with respect to the cut surface 2 are not displayed.

  After setting the cut surface, the position of the cut surface is operated along the line-of-sight direction 301 in the UI (306-1) based on the user operation. The position of the ring-cut surface 1 moves to the near side and the far side along the line-of-sight direction (303) by sliding 306-2 in the horizontal direction. Similarly, the position of the ring-cut surface 2 is moved by sliding the 306-3 in the horizontal direction.

  By setting two ring-cut faces, the solid is cut into two faces on the front and back sides, making it easier to check the depth inside the solid.

  Further, by using a UI such as UI 306-1 or UI 306-2, the user can easily change the position of the cut surface along the line-of-sight direction.

  When a point group showing a color distribution such as an image is displayed together with a solid without setting a circular plane, the distribution of the point group inside the solid cannot be confirmed as shown in FIG. However, if one side of the solid is not displayed using the cut surface, the point group included in the solid can be confirmed as shown in FIG.

  Further, when the line-of-sight direction is changed, the position of the cut surface is also automatically changed, so that the user's trouble can be saved.

  After setting the cut surface, the system reprocesses the object (S206).

  When a plurality of objects are displayed, the analysis / evaluation process of S212 is performed based on an instruction from the user. Details of the processing of S212 will be described later.

  Finally, when the user performs a termination operation (S210), the system performs a termination process (S211).

(Analysis / Evaluation process)
In this embodiment, analysis / evaluation processing between a plurality of objects is performed.

  When the color distribution of the image is displayed as a point cloud and the color reproduction range of the device is displayed as a solid, the analysis / evaluation process is particularly effective for the evaluation / analysis of gamut mapping.

  FIG. 12 shows a UI used for the analysis / evaluation process. In 1101, a list of information on the displayed object is displayed. In the list, the ID of the displayed object, the object name, and the file name of the file storing the color coordinate value indicating the object are displayed.

  A reference object and a comparison object are selected from this list, and analysis / evaluation is performed by processing to be described later. Usually, a point cloud is selected as the reference object, and a solid is selected as the comparison object. However, other objects may be selected for each. When another object is selected, a new object is generated.

  For example, when a solid is selected as the reference object, point clouds are generated with an equal density inside the solid. When a point group is selected as the comparison object, the above-described process of generating Convex Hull is performed, and a solid is generated from the point group.

  When another object is selected, the later-described processing is performed using the newly generated point group or solid.

  By newly generating an object, for example, it is possible to analyze / evaluate color reproduction ranges or color distributions of images.

  After selecting an object, the user selects an evaluation / analysis process from 1102 to 1104.

  Details of each process will be described below.

  When 1102 is selected, the comparison object (point cloud) included in the reference object (solid) and the point cloud not included are displayed in different colors. By separately displaying the color of the point cloud, it is possible to easily grasp the point cloud included in the solid and the point cloud not included in the solid. Here, each of the solid and the point group is selected or generated by the above-described processing.

  In addition, in order to perform color grouping of the point group, it is necessary to determine whether the target color data is inside or outside the solid. Details of the inside / outside determination method in this embodiment will be described later.

  When 1103 is selected, the inside / outside ratio of the point group for the designated solid is calculated and displayed as shown in FIG.

  The inside / outside ratio represents the ratio of the comparison object (point group) (802) included in the reference object (solid) and the point group (803) not included. The inside / outside ratio is calculated by obtaining the number of color data of the point group included (or not included) in the solid with respect to the number of color data of the entire point group. The calculated inside / outside ratio is displayed using a UI such as 801.

  By displaying the inside / outside ratio, the user can more accurately grasp the point cloud included in the solid and the point cloud not included in the solid.

  When 1104 is selected, how much the color data selected by the user among the comparison objects (point group) is inside or outside the reference object (solid) is calculated and displayed. The index at this time can be calculated by various methods. For example, the solid can be represented by a set of tetrahedrons (902) having the center of gravity of the solid as a vertex as shown in FIG. 9A. Therefore, when the point (color data) (901) selected by the user is in the solid, the selected point is included in any tetrahedron in the set of tetrahedrons. Therefore, the position of the selected point in the tetrahedron can be calculated, and the ratio (905) of the distance (904) from the center of gravity (903) to the selected point and the distance from the selected point to the boundary surface (906) (905) ) To calculate how much the selected point is inside the solid.

  Also, if you extend the sides of the tetrahedron with the center of gravity as the vertex outside the solid, how far the selected point is from the solid, using the same method as when the selected point is inside the solid. It can be calculated.

  Then, by displaying the calculated distance or ratio using a UI such as 907 as shown in FIG. 9B, the user can quantitatively grasp the position of the color data with respect to the solid.

(Internal / external judgment method)
A description will be given of an inside / outside determination method for determining whether or not the target color data is inside the solid. A solid can be expressed as a set of multiple tetrahedrons with the center of gravity as one vertex. It has been done.

  In FIG. 7, a point P (701) is a point indicating color data, and a tetrahedron (702) is one of the tetrahedrons constituting the solid. Normal vector for each plane

(703) is a vector from the inside to the outside of each plane of the tetrahedron. FIG. 6 shows one plane (601) constituting the tetrahedron. vector

(604) is a vector from the point P (602) indicating the color data to one point on the tetrahedron (for example, vertex q (605)).

  If normal vector

And vector

Is negative (when the normal vector direction and the vector direction from the point indicating the color data are substantially opposite to each other as shown in FIG. 6), the target color data is outside the tetrahedron. judge. Conversely, if the inner product is a positive value for all planes, the target color data is determined to be a tetrahedron. If the target color data is determined to be out of the tetrahedron for all tetrahedrons constituting the solid, the target color data is determined to be out of the solid. Conversely, if there is at least one tetrahedron that is determined to have the target color data inside, it is determined that the target color data is in the solid.

  With the above method, the inside / outside determination of the target color data for the solid can be performed.

The figure which showed the structure of the circuit of a present Example Flow chart showing object display method The figure explaining the flowchart of FIG. Diagram explaining color distribution processing Example of displaying multiple objects on the color space The figure which shows the plane which constitutes the tetrahedron Diagram showing the tetrahedrons that make up a solid (1) The figure which shows UI which displays inside / outside ratio Figure showing a tetrahedron that forms a solid (2) Diagram showing both point cloud and solid The figure which shows UI for processing when the point cloud and the solid are displayed together

Claims (12)

A color data acquisition step for acquiring a plurality of color data;
A three-dimensional shape generation step of generating a three-dimensional shape of the color gamut of the obtained plurality of color data;
A line-of-sight setting step for setting a viewpoint position and a line-of-sight direction;
A pseudo three-dimensional display step of displaying the generated three-dimensional shape in a pseudo three-dimensional manner;
Based on a user's instruction, a cut surface setting step for setting a position of the cut surface perpendicular to the line-of-sight direction;
A color processing method comprising: a cut surface processing step in which one side of a three-dimensional shape is not displayed at a boundary between a surface where the set circular cut surface and the generated three-dimensional shape intersect. The color data acquisition step acquires at least a first plurality of color data and a second plurality of color data,
The solid shape generation step generates a solid shape indicating a color gamut of the first plurality of color data on a color space,
2. The color processing according to claim 1, wherein the pseudo three-dimensional display step displays the color distribution in a color space indicated by the second plurality of color data together with the generated three-dimensional shape in a pseudo three-dimensional manner. Method.   In the pseudo three-dimensional display step, the color data included in the three-dimensional shape and the color data not included in the three-dimensional shape are displayed in different colors in the color space indicated by the second plurality of color data. The color processing method according to claim 2, wherein a distribution is displayed. Furthermore, based on a user instruction, a color data selection step of selecting color data included in the color distribution,
A distance calculating step of calculating a distance between the center of gravity of the three-dimensional shape and the selected color data;
The color processing method according to claim 2, further comprising a distance display step of displaying the calculated distance.   The color processing method according to claim 1, wherein the ring-cut surface setting step sets a position of the ring-cut surface based on a user instruction.   The color processing method according to claim 1, wherein the ring cutting surface setting step sets a plurality of ring cutting surfaces.   The color processing method according to claim 1, further comprising a viewpoint changing step of changing the set viewpoint based on a user instruction. A color data acquisition step of acquiring at least a first plurality of color data and a second plurality of color data;
A three-dimensional shape generation step of generating a three-dimensional shape indicating a color gamut of the first plurality of color data;
An inside / outside ratio display step of displaying a ratio between the number of color data included in the three-dimensional shape and the number of color data not included in the three-dimensional shape in the color distribution on the color space indicated by the second plurality of color data. A color processing method characterized by comprising: Color data acquisition means for acquiring a plurality of color data;
A solid shape generating means for generating a solid shape of a color gamut of the acquired plurality of color data;
Line-of-sight setting means for setting the viewpoint position and line-of-sight direction;
Pseudo three-dimensional display means for displaying the generated three-dimensional shape in a pseudo three-dimensional manner;
Based on a user instruction, a ring-cut surface setting means for setting a position of the ring-cut surface perpendicular to the line-of-sight direction;
A color processing apparatus, comprising: a cut surface processing unit that does not display one side of a three-dimensional shape, with a boundary between the set circular surface and the generated three-dimensional shape as a boundary. Color data acquisition means for acquiring at least a first plurality of color data and a second plurality of color data;
A solid shape generating means for generating a solid shape indicating a color gamut of the first plurality of color data;
An internal / external ratio display means for displaying a ratio between the number of color data included in the three-dimensional shape and the number of color data not included in the three-dimensional shape in the color distribution on the color space indicated by the second plurality of color data. A color processing apparatus comprising:   A non-transitory computer-readable storage medium storing a program for causing a computer to execute the color processing method according to claim 1.   A computer-readable recording medium recording a program for causing a computer to execute the color processing method according to claim 1.

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