Color conversion coefficient preparation apparatus, color conversion coefficient preparation method, storage medium, and color conversion system

A color conversion coefficient preparation apparatus for preparing color conversion coefficients to convert n color values including black in a first machine-dependent color space into n color values including black in a second machine-dependent color space, the color conversion coefficient preparation apparatus comprising:

• a first TRC preparation section for preparing a color conversion coefficient for each color to convert the n color values in the first machine-dependent color space into n color values in a first adjustment-machine-dependent color space with adjusted gradation of a single color in the first machine-dependent color space;
• a second TRC preparation section for preparing a color conversion coefficient for each color to convert n color values in a second adjustment-machine-dependent color space with adjusted gradation of a single color in the second machine-dependent color space into the n color values in the second machine-dependent color space;
• a K conversion LUT preparation section for preparing a one-dimensional lookup table for converting the value of black in the first adjustment-machine-dependent color space into the value of black in the second adjustment-machine-dependent color space with the characteristic of the value of black preserved;
• and
• an n-dimensional DLUT preparation section for preparing an n-dimensional lookup table for converting the n color values in the first adjustment-machine-dependent color space into the (n−1) color values except for black in the second adjustment-machine-dependent color space.

A color conversion coefficient preparation apparatus for preparing color conversion coefficients to convert n color values including black in a first machine-dependent color space into n color values including black in a second machine-dependent color space, the color conversion coefficient preparation apparatus comprising:

• a first TRC preparation section for preparing a color conversion coefficient for each color except black to convert the (n−1) color values except for black in the first machine-dependent color space into (n−1) color values except for black in a first adjustment-machine-dependent color space with adjusted gradation of a single color in the first machine-dependent color space;
• a second TRC preparation section for preparing a color conversion coefficient for each color to convert n color values in a second adjustment-machine-dependent color space with adjusted gradation of a single color in the second machine-dependent color space into the n color values in the second machine-dependent color space;
• a K conversion LUT preparation section for preparing a one-dimensional lookup table for converting the value of black in the first machine-dependent color space into the value of black in the second adjustment-machine-dependent color space with the characteristic of the value of black preserved;
• and
• an n-dimensional DLUT preparation section for preparing an n-dimensional lookup table for converting the (n−1) color values except for black in the first adjustment-machine-dependent color space and the value of black in the first machine-dependent color space into the (n−1) color values except for black in the second adjustment-machine-dependent color space.

A color conversion coefficient preparation apparatus for preparing color conversion coefficients to convert n color values including black in a first machine-dependent color space into n color values including black in a second machine-dependent color space, the color conversion coefficient preparation apparatus comprising:

• a first TRC preparation section for preparing a color conversion coefficient for each color to convert the n color values in the first machine-dependent color space into n color values in a first adjustment-machine-dependent color space with adjusted gradation of a single color in the first machine-dependent color space;
• a K conversion LUT preparation section for preparing a one-dimensional lookup table for converting the value of black in the first adjustment-machine-dependent color space into the value of black in the second machine-dependent color space with the characteristic of the value of black preserved;
• and
• an n-dimensional DLUT preparation section for preparing an n-dimensional lookup table for converting the n color values in the first adjustment-machine-dependent color space into the (n−1) color values except for black in the second machine-dependent color space.

A color conversion coefficient preparation apparatus for preparing color conversion coefficients to convert n color values including black in a first machine-dependent color space into n color values including black in a second machine-dependent color space, the color conversion coefficient preparation apparatus comprising

• a first TRC preparation section for preparing a color conversion coefficient for each color except black to convert the (n−1) color values except for black in the first machine-dependent color space into (n−1) color values except for black in a first adjustment-machine-dependent color space with adjusted gradation of a single color in the first machine-dependent color space;
• a K conversion LUT preparation section for preparing a one-dimensional lookup table for converting the value of black in the first machine-dependent color space into the value of black in the second machine-dependent color space with the characteristic of the value of black preserved;
• and
• an n-dimensional DLUT preparation section for preparing an n-dimensional lookup table for converting the (n−1) color values except for black in the first adjustment-machine-dependent color space and the value of black in the first machine-dependent color space into the (n−1) color values except for black in the second machine-dependent color space.

A color conversion coefficient preparation apparatus for preparing color conversion coefficients to convert n color values including black in a first machine-dependent color space into n color values including black in a second machine-dependent color space, the color conversion coefficient preparation apparatus comprising:

• a first TRC preparation section for preparing a color conversion coefficient for each color to convert n color values in a second adjustment-machine-dependent color space with adjusted gradation of a single color in the second machine-dependent color space into the n color values in the second machine-dependent color space;
• a K conversion LUT preparation section for preparing a one-dimensional lookup table for converting the value of black in the first machine-dependent color space into the value of black in the second adjustment-machine-dependent color space with the characteristic of the value of black preserved;
• and
• an n-dimensional DLUT preparation section for preparing an n-dimensional lookup table for converting the n color values in the first machine-dependent color space into the (n−1) color values except for black in the second adjustment-machine-dependent color space.

A color conversion coefficient preparation apparatus for preparing color conversion coefficients to convert n color values including black in a first machine-dependent color space into n color values including black in a second machine-dependent color space, the color conversion coefficient preparation apparatus comprising a K preservation n-dimensional DLUT preparation section for preparing an n-dimensional lookup table for converting the n color values in the first machine-dependent color space into the n color values in the second machine-dependent color space with the characteristic of black preserved,

• wherein the K preservation n-dimensional DLUT preparation section comprises:
• a color specification value prediction section for predicting a color specification vector in a machine-independent color space from the n color values in the first machine-dependent color space;
• a K conversion section for converting the value of black in the first machine-dependent color space into the value of black in the second machine-dependent color space with the characteristic of the value of black preserved;
• and
• an (n−1) color prediction section for predicting (n−1) color values except for black in the second machine-dependent color space from the color specification vector in the machine-independent color space predicated by the color specification value prediction section and the value of black provided by the K conversion section.

A computer-readable storage medium storing a program for:

• preparing a color conversion coefficient for each color to convert n color values in a first machine-dependent color space into n color values in a first adjustment-machine-dependent color space with adjusted gradation of a single color in the first machine-dependent color space;
• preparing a color conversion coefficient for each color as inverse conversion to conversion of n color values in a second machine-dependent color space to n color values in a second adjustment-machine-dependent color space with adjusted gradation of a single color in the second machine-dependent color space;
• and
• preparing an n-dimensional lookup table for converting the n color values in the first adjustment-machine-dependent color space into the n color values in the second adjustment-machine-dependent color space with the characteristic of black preserved by using the conversion result from the first machine-dependent color space to the first adjustment-machine-dependent color space and the conversion result from the second machine-dependent color space to the second adjustment-machine-dependent color space.