Method and means for tetrahedron/octahedron packing and tetrahedron extraction for function approximation

Patent 5390035 Issued on February 14, 1995. Estimated Expiration Date:

December 23, 2012. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Application

No. 996805 filed on 12/23/1992

US Classes:

358/518, Color correction358/523, With memory for storage of conversion data358/525Interpolation

Examiners

Primary: Rogers, Scott A.

Attorney, Agent or Firm

Baker, Maxham, Jester & Meador

Foreign Patent References

2-206973 JP. 02/25/1990
2-226869 JP. 02/25/1990
1595122 GB. 08/25/1981

International Class

H04N 001/46

Abstract

The invention concerns the conversion of an input color to an output color using a multi-variable function having an input domain in a first three-dimensional color space and output range in a second m-dimensional color space. The conversion from input to output color subdivides the input domain into polyhedra defined by planar grids of points connected to form a plurality of triangles. The planar grids are projected into the remaining dimension of the function domain. When an input color value is presented, the multi-variable function is used to approximate the input value by computing an approximation of the multi-variable function, which provides a value in the output range. A tetrahedron containing the input color value is extracted from the function domain. The values of the multi-variable function at the tetrahedron vertices are obtained by interpolation. The tetrahedron is subdivided into subtetrahedra. The volumes of the subtetrahedra are calculated and multiplied by the function values. The products are added together and normalized to the volume of the extracted tetrahedron to produce an approximation of the input color. The approximation is provided as the value of the output color.

Other References

"Color Correction Technique for Hard Copies by 4-Neighbors Interpolation Method", Kanamori et al., Journal of Imaging Science and Technology, vol. 36, No. 1, Jan.-Feb. 1992, pp. 73-80
"The Gamut of Real Surface Colours", M. R. Pointer, Research Division, Kodak Limited, Color Research Application, vol. 5, No. 3, Fall 1980, pp. 145-155
"A Novel Color Transformation Algorithm And It's Application" by Katsuhiro et al.; Image Processing Algorithm and Tech.; vol. 1244; 199