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:
Apr. 18, 2000
Filed:
May. 30, 1997
Bradly J Foster, Fort Collins, CO (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
Data values representative of a source image are processed with a dither matrix having dither values corresponding to pixel locations in the source image. The dither matrix has dimensions n.times.n, where n is modulo 4 and an integer value m exists such that m.multidot.m=n. The dither matrix is typically a 4.times.4 matrix. The dither values are arranged in the dither matrix such that each row, column, diagonal and m.times.m submatrix in the dither matrix adds to substantially the same value, preferably the sum of all dither values in the dither matrix divided by n. A dither value corresponding to a pixel location is accessed in the dither matrix. An initial data value associated with the pixel location is combined with the accessed dither value, typically by adding, to provide an intermediate value. The intermediate value is clamped and truncated to provide a dithered data value. Where each pixel is represented by two or more data values, such as color values, a dither matrix is associated with each parameter. Preferably, the sum of the selected dither matrices is a matrix having matrix values that are substantially the same.