US 6,618,500 B1Granted

Color conversion matrix based on minimal surface theory

AssigneesSony Corporation, Sony Electronics Inc.

InventorThomas P. Dawson

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Abstract

A method for color conversion applying minimal surface theory to the formation of the volumes in a three-dimensional color cube. Volume center points on the color cube are selected as entries in a color look-up table, and these center points are plotted on the color cube. Spheres centered about each volume center point are created, and the discrete locations in the color cube falling within each sphere are associated with the CLUT entry corresponding to that volume center point. The radii of the spheres are incrementally increased, and the discrete locations falling within the enlarged spheres are associated with the corresponding CLUT entry. As the spheres enlarge they begin to intersect. The intersection of the spheres form planes which divide the discrete locations such that each discrete location is associated with the closest volume center point.

Claims17

Dependent claims

A method for color conversion using a three-dimensional color cube, each axis of the color cube representing a variable in a color model, in which the color cube defines n discrete locations each having a color the method comprising:

determining m center points in said color cube, n being less than n;
performing a sphere-creating process comprising:
creating a plurality of spheres, each sphere being centered on a corresponding one of said center points and having a radius R;
identifying all discrete locations located within each sphere;
and
associating each identified discrete location with the center point of the sphere within which that discrete location is located;
and
iteratively performing said sphere-creating process, wherein each iteration uses spheres of a radius incrementally larger than the radius in the preceding iteration, and for each identified discrete location not already associated with one of said center points associating said identified discrete location to the center point corresponding to the incrementally larger sphere within which said identified discrete location is located,
wherein said sphere-creating process is repeated until all discrete locations have an associated center point.

6 more elements

A method for color conversion of a digital image on a computer, comprising:

providing a data structure representing a three-dimensional color cube, each axis of the color cube representing a variable in a color model, said color cube defining a plurality of discrete locations;
determining a plurality of center points in said color cube;
associating each of said plurality of center points with an entry in a color look-up table;
storing a color value for each of said plurality of center points in the color look-up table entry corresponding to said center point;
performing a sphere-creating process on said computer said sphere-creating process comprising:
creating a sphere having a radius R about each center point said sphere comprised of a plurality of circles drawn in parallel planes in said color cube;
for each sphere, identifying all discrete locations located within said plurality of circles within each sphere;
associating each identified discrete location with the center point of the circle containing said identified discrete location, said associating comprising assigning a mapping value of the color look-up table entry corresponding to said center point to a memory location in said data structure corresponding to said identified discrete location;
and
iteratively performing said sphere-creating process, wherein each iteration uses spheres of a radius incrementally larger than the radius in the preceding iteration, and for each identified discrete location not already associated with one of said center points, associating said identified discrete location to the center point corresponding to the incrementally larger sphere within which said identified discrete location is located,
wherein said sphere-creating process is repeated until all discrete locations have an associated center point.

8 more elements

Dependencies are inferred from the claim text.