Color conversion apparatus and method with precision enhancement in color conversion
AssigneeMinolta Co., Ltd.
InventorTakayuki Nabeshima
Life of this patent
Estimating the term…
Abstract
A method of converting image data from L*a*b* color space into CMYK color space by using a three-dimensional direct mapping table employs only data of lattice points existing within the color space. 8-point interpolation is used when all the lattice points constituting a lattice component containing input data are included in the color space, while another interpolation processing (e.g. 4-point interpolation) is employed for a lattice component partially existing outside the color space by using only lattice point data within the color space. Enhancement of precision in color conversion is thus achieved.
Claims15
A color conversion apparatus comprising:
- a color conversion table for receiving input image data represented by a first color space to output color-converted data represented by a second color space, said color-converted data corresponding to lattice points of a lattice component containing the input image data in said first color space;
- interpolation processing means for performing interpolation processing using the color-converted data output from said color conversion table;
- and
- a switching unit for changing lattice points corresponding to the color-converted data to be used by said interpolation processing means, according to position of said input image data in said first color space.
A color conversion method comprising the steps of:
- receiving input image data represented by a first color space to output color-converted data represented by a second color space, said color-converted data corresponding to lattice points of a lattice component containing said input image data in said first color space;
- performing interpolation processing using said output color-converted data;
- and
- changing lattice points corresponding to the color-converted data to be used in said interpolation processing, according to position of said input image data in said first color space.
A color conversion apparatus comprising:
- a color conversion table for receiving input image data represented by a first color space to output color-converted data represented by a second color space, said color-converted data corresponding to lattice points of a lattice component containing the input image data in said first color space;
- a first interpolation processing unit for performing interpolation processing using color-converted data output from said color conversion table;
- a second interpolation processing unit for performing interpolation processing using color-converted data corresponding to lattice points different from those used by said first interpolation processing unit;
- and
- a switching unit for making a switch between said first interpolation processing unit and said second interpolation processing unit, according to position of said input image data in said first color space.
A color conversion apparatus comprising:
- a color conversion table for receiving input image data represented by a first color space to output color-converted data represented by a second color space, said color-converted data corresponding to lattice points of a lattice component containing the input image data in said first color space;
- a storage unit for storing distance information indicating distance between said lattice points;
- and
- an interpolation processing unit for performing interpolation processing using the color-converted data output from said color conversion table and the distance information stored in said storage unit.
A color conversion method comprising the steps of:
- receiving input image data represented by a first color space to output color-converted data represented by a second color space, said color-converted data corresponding to lattice points of a lattice component containing said input image data in said first color space;
- and
- performing interpolation processing using said output color-converted data and distance information indicating distance between said lattice points.
Dependencies are inferred from the claim text.