Gamut description and visualization

A computer-implemented method for comparing a first color gamut able to be produced by a color generating apparatus upon a given medium with a second color gamut, the method comprising the steps of:

• a) using a first collection of sample color points to create a first hull in the color space, each sample color point in the first collection defining a location in at least a three-dimensional color space and corresponding to a color in the first color gamut,
• the set of all of the points disposed on the surface of the first hull or within the volume enclosed thereby representing the first color gamut,
• all of the color points in the first collection of sample color points being disposed on the surface of the hull or within the volume defined thereby;
• b) using a second collection of sample color points to create a second hull in the color space, each sample color point in the second collection defining a location in at least a three-dimensional color space and corresponding to a color in the second color gamut,
• the set of all of the points disposed on the surface of the second hull or within the volume enclosed thereby representing the second color gamut,
• all of the color points in the second collection of sample color points being disposed on the surface of the second hull or within the volume defined thereby;
• and
• c) combining the first and second hulls thereby to create a third hull in the color space representing the region of overlap or the region of exclusion between the first color gamut and the second color gamut,
• wherein the combining step is implemented using a calculation, and further wherein
• when the third hull represents the region of overlap, each point disposed on the surface of the third hull or within the volume enclosed thereby represents a color within both the first and the second color gamuts, and
• when the third hull represents the region of exclusion, each point disposed on the surface of the third hull or within the volume enclosed thereby represents a color within the first gamut but not within the second gamut.

A computer-implemented method for comparing a first color gamut able to be produced by a color generating apparatus upon a given medium with a second color gamut, the method comprising the steps of:

• a) using a first collection of sample color points to create a plurality of boundary surfaces collectively defining a first hull in the color space, each sample color point in the first collection defining a location in at least a three-dimensional color space and corresponding to a color in the first color gamut,
• the set of all of the points disposed on the surface of the first hull or within the volume enclosed thereby representing the color gamut able to be produced by the color generating apparatus,
• all of the color points in the first collection of sample color points being disposed on the surface of the first hull or within the volume defined thereby;
• b) using a second collection of sample color points to create a plurality of boundary surfaces collectively defining a second hull in the color space, each sample color point in the second collection defining a location in at least a three-dimensional color space and corresponding to a color in the second color gamut,
• the set of all of the points disposed on the surface of the second hull or within the volume enclosed thereby representing the second color gamut,
• all of the color points in the second collection of sample color points being disposed on the surface of the second hull or within the volume defined thereby;
• c) combining the first and second hulls thereby to create a plurality of boundary surfaces collectively defining a third hull in the color space representing a region of overlap of the first and second gamuts,
• such that each point disposed on the surface of the third hull or within the volume enclosed thereby representing a color that is within both the first and the second color gamuts,
• wherein the combining step is implemented using a calculation.

A computer-implemented method for comparing a first color gamut able to be produced by a color generating apparatus upon a given medium with a second color gamut, the method comprising the steps of:

• a) using a first collection of sample color points to create a plurality of boundary surfaces collectively defining a first hull in the color space, each sample color point in the first collection defining a location in at least a three-dimensional color space and corresponding to a color in the first color gamut,
• the set of all of the points disposed on the surface of the first hull or within the volume enclosed thereby representing the color gamut able to be produced by the color generating apparatus,
• all of the color points in the first collection of sample color points being disposed on the surface of the first hull or within the volume defined thereby;
• b) using a second collection of sample color points to create a plurality of boundary surfaces collectively defining a second hull in the color space, each sample color point in the second collection defining a location in at least a three-dimensional color space and corresponding to a color in the second color gamut,
• the set of all of the points disposed on the surface of the second hull or within the volume enclosed thereby representing the second color gamut,
• all of the color points in the second collection of sample color points being disposed on the surface of the second hull or within the volume defined thereby;
• c) combining the first and second hulls thereby to create a plurality of boundary surfaces collectively defining a third hull in the color space representing the region of exclusion of the first and second gamuts,
• such that each point disposed on the surface of or within the volume enclosed by the third hull representing a color that is within the first gamut but not within the second color gamut,
• wherein the combining step is implemented using a calculation.

A computer-implemented method for comparing a first color gamut able to be produced by a color generating apparatus upon a given medium with a second color gamut, the method comprising the steps of:

• a) using a first collection of sample color points to create a plurality of boundary surfaces collectively defining a first hull in the color space, each sample color point in the first collection defining a location in at least a three-dimensional color space and corresponding to a color in the first color gamut,
• the set of all of the points disposed on the surface of the first hull or within the volume enclosed thereby representing the color gamut able to be produced by the color generating apparatus,
• all of the color points in the first collection of sample color points being disposed on the surface of the hull or within the volume defined thereby;
• b) using a second collection of sample color points to create a plurality of boundary surfaces collectively defining a second hull in the color space, each sample color point in the second collection defining a location in at least a three-dimensional color space and corresponding to a color in the second color gamut,
• the set of all of the points disposed on the surface of the second confining hull or within the volume enclosed thereby representing the second color gamut,
• all of the color points in the second collection of sample color points being disposed on the surface of the second hull or within the volume defined thereby;
• c) for each of a plurality of locations along a predetermined reference line in the color space, generating a visual display of the contour in a plane perpendicular to that reference line that is produced by the intersection of one or both the first and the second hulls with that plane, thereby to ascertain qualitatively the degree of alignment of the first and second hulls along the reference line.

A computer-implemented method for determining whether a predetermined candidate color corresponding to a predetermined color point in at least a three-dimensional color space lies within a color gamut able to be produced by a color generating apparatus upon a given medium, the method comprising the steps of:

• a) using a first collection of sample color points to create a plurality of boundary surfaces collectively defining a first hull in the color space, each sample color point in the first collection defining a location in at least a three-dimensional color space and corresponding to a color in the first color gamut,
• the set of all the points disposed on the surface of the full or within the volume enclosed thereby representing the color gamut able to be produced by the color generating apparatus;
• and
• b) determining whether the point in the color space corresponding to the predetermined candidate color lies on the surface of the hull or within the volume defined thereby by casting a ray from the candidate color point and counting the number of intersections of the ray with said first hull such that an odd number of intersections of said ray with said first hull indicates the candidate color point is inside the first hull, wherein prior to the determination, scaling the collection of sample color points and the predetermined color point using a scale factor determined in accordance with the values in the color space of the sample color points and the value in the color space of the predetermined color point.