Color conversion apparatus

A method of determining endpoints of an interpolation interval for use in conversion of an input image in an input colour space having a first set of primary colour components to an output image in an output colour space having a second set of primary colour components different from the first set, said method comprising the steps of:

• dividing at least one primary colour of said input colour space into a plurality of intervals,
• storing the endpoints of said plurality of intervals,
• resolving said intervals into a plurality of groups, with adjacent intervals being resolved into different groups,
• determining which of said groups include a selected one of said plurality of intervals having a preselected pixel of said image, and
• simultaneously retrieving the endpoints of said selected one interval using an offset addressing variable between each one of the groups.

Colour conversion apparatus for converting an input image in an input colour space to an output image in an output colour space, wherein at least one primary colour of said input colour space is divided into a plurality of intervals having endpoints and wherein, the output colour space has output colour values corresponding to the endpoint, said apparatus comprising:

• determining means for determining, for each input pixel in the input image, the output colour values corresponding to the endpoints closest to the input pixel;
• and
• interpolating means for interpolating between said output colour values corresponding to the endpoints closest to the input pixel to derive an output colour value in said output colour space;
• wherein said determining means comprises:
• storage means for storing the output colour values corresponding to said endpoints, wherein output colour values corresponding to adjacent endpoints are group into different groups;
• and
• retrieving means for simultaneously retrieving the output colour values corresponding to the endpoints closest to said input pixel using an offset addressing variable between each one of the groups.

A method for converting an input image in an input colour space to an output image in an output colour space, each of said images comprising a plurality of pixels comprised of a plurality of primary colour components of the respective colour space, wherein the input colour space is divided into a number of volumes each having m vertices and the output colour space has output colour values corresponding to the vertices of said volumes as interpolation points, said method comprising the steps of:

• determining, for each pixel in the input image, the closest interpolation points;
• and
• interpolating between said closest interpolation points to derive an output colour value in said output colour space,
• wherein said determining step comprises:
• storing, for each volume, m output colour values corresponding to the m vertices of said volume in m separate storage means;
• and
• simultaneously accessing the m storage means and supplying the m output colour values corresponding to the m vertices closest to said input pixel as said closest interpolation points.

Colour conversion apparatus for converting an input image in an input colour space to an output image in an output colour space, each of said images comprising a plurality of pixels comprised of a plurality of primary colour components of the respective colour space, wherein the input colour space is divided into a number of volumes each having m vertices and the output colour space has output colour values corresponding to the vertices of said volumes as interpolation points, said apparatus comprising

• determining means for determining, for each pixel in the input image, the closest interpolation points;
• and
• interpolating means for interpolating between said closest interpolation points to derive an output colour value in said output colour space,
• wherein said determining means comprises:
• m separate storage means for storing, for each volume, m output colour values corresponding to the m vertices of said volume;
• and
• accessing means for simultaneously accessing the m storage means and supplying the m output colour pixels corresponding to the m vertices closest to said input pixel as said closest interpolation points.