Method of creating color conversion table and image processing apparatus

An image processing apparatus for creating a second color conversion table for converting an input color signal value into an output color signal value, said apparatus comprising:

• means for creating a first color conversion table for converting an input color signal value into an output color signal value by using a first target color corresponding to color reproducibility with emphasis on coincidence of colorimetry;
• means for creating a color-space correspondence table for converting from a color space of the output color signal value into another predetermined color space;
• means for determining a first output color signal value corresponding to a second target color, which is determined for a grid point of the second color conversion table to be created, by an interpolation computation of the first color conversion table;
• means for setting a neighboring region of the determined first output color signal value and determining a second output color signal value that is most approximate to the second target color in the neighboring region, by using the color-space correspondence table;
• and
• means for setting the determined second output color signal value as grid point data of the grid point of the second color conversion table to be created,
• wherein the second color conversion table is any one of a table associated with color reproducibility with emphasis on tone, a table associated with color reproducibility with emphasis on chroma, or a table associated with color reproducibility with emphasis on memory color, and
• wherein said second target color is a color of reproducibility with emphasis on tone, a color of reproducibility with emphasis on chroma, or a color of reproducibility with emphasis on memory color.

A method of estimating an output color signal by means of interpolation computation using a second color conversion table for converting an input color signal value into an output color signal value, said method comprising:

• using a processor to perform the steps of:
• creating a first color conversion table for converting an input color signal value into an output color signal value by using a first target color corresponding to color reproducibility with emphasis on coincidence of colorimetry, and a color-space correspondence table for converting from a color space of the output color signal value into another predetermined color space;
• determining a first output color signal value corresponding to a second target color, which is determined for a grid point of the second color conversion table to be created, by an interpolation computation for the first color conversion table;
• and
• setting a neighboring region of the determined first output color signal value and determining a second output color signal value that is most approximate to the second target color in the neighboring region, by using the color-space correspondence table,
• wherein the second color conversion table is any one of a table associated with color reproducibility with emphasis on tone, a table associated with color reproducibility with emphasis on chroma, or a table associated with color reproducibility with emphasis on memory color, and
• wherein said second target color is a color of reproducibility with emphasis on tone, a color of reproducibility with emphasis on chroma, or a color of reproducibility with emphasis on memory color.

A program stored on a non-transitory computer-readable medium, the program for executing processing of creating a second color conversion table for converting an input color signal value into an output color signal value, and for causing an image processing apparatus to process code of the program, wherein the program comprises code for:

• creating a first color conversion table for converting an input color signal value into an output color signal value by using a first target color corresponding to color reproducibility with emphasis on coincidence of colorimetry, and a color-space correspondence table for converting from a color space of the output color signal value into another predetermined color space;
• determining a first output color signal value corresponding to a second target color, which is determined for a grid point of the second color conversion table to be created, by an interpolation computation of the first color conversion table;
• setting a neighboring region of the determined first output color signal value and determining a second output color signal value that is most approximate to the second target color in the neighboring region, by using the color-space correspondence table;
• and
• setting the determined second output color signal value as grid point data of the grid point of the second color conversion table to be created,
• wherein the second color conversion table is any one of a table associated with color reproducibility with emphasis on tone, a table associated with color reproducibility with emphasis on chroma, or a table associated with color reproducibility with emphasis on memory color, and
• wherein said second target color is a color of reproducibility with emphasis on tone, a color of reproducibility with emphasis on chroma, or a color of reproducibility with emphasis on memory color.

A program stored on a non-transitory computer-readable medium, the program for executing processing of creating a second color conversion table for converting an image signal of a predetermined color space into an image signal dependent on an output device, said program comprising code for:

• creating a first color conversion table for converting an image signal of the predetermined color space into an image signal dependent on the output device by using a first target color corresponding to color reproducibility with emphasis on coincidence of colorimetry;
• determining an image signal depending on the output device, said image signal being approximate to a second target value corresponding to a grid point of the second color conversion table to be created, by using the first color conversion table;
• and
• setting the determined image signal dependent on the output device as grid point data of the second color conversion table to be created,
• wherein the second color conversion table is any one of a table associated with color reproducibility with emphasis on tone, a table associated with color reproducibility with emphasis on chroma, or a table associated with color reproducibility with emphasis on memory color, and
• wherein said second target color is a color of reproducibility with emphasis on tone, a color of reproducibility with emphasis on chroma, or a color of reproducibility with emphasis on memory color.

A method of creating a second color conversion table for converting an input color signal value into an output color signal value, said method comprising:

• using a processor to perform the steps of:
• creating a first color conversion table for converting an input color signal value into an output color signal value by using a first target color, and a color space correspondence table for converting from a color space of the output color signal value into another predetermined color space;
• determining a first output color signal value corresponding to a second target color, which is determined for a grid point of the second color conversion table to be created, by an interpolation computation of the first color conversion table;
• setting a neighboring region of the determined first output color signal value and determining a second output color signal value that is most approximate to the second target color in the neighboring region, by using the color space correspondence table;
• and
• setting the determined second output color signal value as grid point data of the grid point of the second color conversion table to be created,
• wherein the first color conversion table is any one of a table associated with color reproducibility with emphasis on coincidence of colorimetry, a table associated with color reproducibility with emphasis on tone, a table associated with color reproducibility with emphasis on chroma, or a table associated with color reproducibility with emphasis on memory color, and the second color conversion table is a table other than the first color conversion table and is any one of a table associated with color reproducibility with emphasis on tone, a table associated with color reproducibility with emphasis on chroma, or a table associated with color reproducibility with emphasis on memory color, and
• wherein said first target color is a color of reproducibility with emphasis on coincidence of colorimetry, a color of reproducibility with emphasis on tone, a color of reproducibility with emphasis on chroma, or a color of reproducibility with emphasis on memory color, and said second target color is a color other than the first target color and is any one of a color of reproducibility with emphasis on coincidence of colorimetry, a color of reproducibility with emphasis on tone, a color of reproducibility with emphasis on chroma, or a color of reproducibility with emphasis on memory color.