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:
Jun. 10, 1997
Filed:
Feb. 23, 1996
Alan E Cariffe, San Diego, CA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A method converts a multi-pixel gray level raster image to a multi-pixel binary raster image, with the gray level raster image including up to P gray level values. The method first arranges the P gray level values into an ordered list. A plurality of dither matrices are then derived, each including M threshold values, each value therein being a threshold value which, when compared to a gray level pixel value enables assignment of a binary value to the pixel. In general, M and P are different integer values. If M is greater than P, the method inserts the P ordered gray level value list into one dither matrix and then inserts into the same one dither matrix at least a further portion of the ordered list, commencing with the first gray level value of the ordered list, until there is no further room for any further insertions in the one dither matrix. Then, the method inserts into a next dither matrix the portion of the ordered list not inserted into the one dither matrix and continues insertion of the ordered list until there is no further room for any further insertions. The method repeats the previous steps until the plurality of dither matrices have been derived. If M is less than P, the method inserts an initial portion of the ordered gray level list into one dither matrix until there is no further room for any further value insertions and then inserts into a next dither matrix a further portion of the ordered list not inserted into the one dither matrix. Thereafter, one or the other sets of dither matrices, as the case may be, is logically tiled over the multi-pixel gray level raster image to enable derivation of the multi-pixel binary level raster image.