Method and apparatus for transforming color gamut from one color space to another
AssigneeXerox Corporation
InventorDavid P. Butler
Life of this patent
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Abstract
A method for transforming color gamut from a first color space to a second color space, includes dividing the first color space into a first plurality of regions in an objective space; dividing a subset of the second color space into a second plurality of regions in the objective space; mapping a first region of said first plurality into a first region of said second plurality substantially without change; mapping a second region of said first plurality comprising an upper gamut of the first color space into a complementary second region of said second plurality; and mapping a third region of said first plurality comprising a lower gamut of the first color space with a gamma correction into a complementary third region of said second plurality.
Claims14
A method for transforming color gamut from a first color space to a second color space, comprising:
- dividing the first color space into a first plurality of regions in an objective space;
- dividing a subset of the second color space into a second plurality of regions in the objective space;
- mapping a first region of said first plurality comprising a center gamut of the first color space into a first region of said second plurality substantially without change;
- mapping a second region of said first plurality comprising an upper gamut of the first color space into a complementary second region of said second plurality;
- and
- mapping a third region of said first plurality comprising a lower gamut of the first color space with a gamma correction into a complementary third region of said second plurality.
Apparatus for transforming a digital color image comprising a plurality of first data elements, from a first color space to a second color space, comprising:
- a memory storing a lookup table comprising a mapping of first data values in the first color space to second data values in the second color space, the lookup table being generated by:
- dividing the first color space into a first plurality of regions in an objective space;
- dividing a subset of the second color space into a second plurality of regions in the objective space;
- mapping a first region of said first plurality comprising a center gamut of the first color space into a first region of said second plurality substantially without change;
- mapping a second region of said first plurality comprising an upper gamut of the first color space into a complementary second region of said second plurality;
- and
- mapping a third region of said first plurality comprising a lower gamut of the first color space with a gamma correction into a complementary third region of said second plurality;
- and
- a processor, responsive to the lookup table and for each first data element having a first data value, for locating a corresponding second data value.
In a system having a color image source device and a color image destination device having non-coincident color gamuts such that a plurality of colors within a color gamut of the source device are out of gamut colors outside a color gamut of the destination device, a method of transforming source device colors to destination device colors, comprising:
- storing in advance in fixed, non-volatile, machine-readable form a correspondence between gamut colors that are source device colors and respective destination device colors, said correspondence being derived by:
- dividing the source space into a first plurality of regions in an objective space;
- dividing a subset of the destination color space into a second plurality of regions in the objective space;
- mapping a first region of said first plurality comprising a center gamut of the first color space into a first region of said second plurality substantially without change;
- mapping a second region of said first plurality comprising an upper gamut of the first color space into a complementary second region of said second plurality;
- and
- mapping a third region of said first plurality comprising a lower gamut of the first color space with a gamma correction into a complementary third region of said second plurality;
- and
- transforming source device colors to respective destination device colors based on said correspondence.
Dependencies are inferred from the claim text.