The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 11, 2003
Filed:
Nov. 12, 1997
Jun Zhao, San Jose, CA (US);
Timothy L. Kohler, Mountain View, CA (US);
Jonathan Hui, Fremont, CA (US);
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
To generate a color palette having m colors (such as 2 =256 colors) from a color image described in a color space, pixel image data corresponding to the color image is first obtained. A frequency of occurrence for each color in the pixel image data is then determined. Each color in the pixel image data is assigned to one of a predetermined number of cells into which the color space has been partitioned, the predetermined number being not greater than m. The most commonly occurring color is selected in each cell in which a color exists, so as to obtain n palette colors. A vote value is calculated for each unselected color, the vote value being based at least in part on the frequency of occurrence of the color in the pixel image and a weighting factor based on a rank of the color in its corresponding cell, the unselected colors being the colors not selected in the first selecting step. Thereafter, m-n colors are selected as the unselected colors with the highest vote values. Also, input colors in a color image described in a color space are mapped to a reduced palette of m colors derived by partitioning the color space into a predetermined number of cells, there being at least one palette color in each cell that includes an input color. The mapping is performed by determining in which cell each input color lies, and mapping each input color to the closest palette color from among all palette colors in the cell identified for that input color.