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:
May. 26, 1987
Filed:
Apr. 12, 1985
Yi-Hsin Chen, Croton-on-Hudson, NY (US);
Frederick C Mintzer, Shrub Oak, NY (US);
Keith S Pennington, Somers, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An electronic processing system for reproducing mixed images, i.e., original images having areas of continuous tone and areas of text, in such a manner that both areas are of balanced, good quality in the reproduction. The image to be reproduced is (1) divided into non-overlapping 4.times.4 blocks of pixels or picture elements, and, (2) each block is classified as either of TEXT or IMAGE, based on the values of the 16 pixels within it. The classification is improved by (3) eliminating short runs of blocks with the same classification. The pixel values are then adjusted by appropriately (4) thresholding those in the TEXT blocks and, (5) averaging those in the IMAGE blocks. The IMAGE block values are quantized to one of 17 levels using an improved error diffusing process and then mapped onto a 4.times.4 pattern preparatory to (6) merging the binary images for the TEXT and IMAGE areas. Converting to various patterns to suit the output device such as a specific printer, is possible by permitting the conversion of the bits for an IMAGE block from one pattern table to another.