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:
Jul. 11, 2000
Filed:
Jul. 09, 1997
Hakan Ancin, Cupertino, CA (US);
Anoop Bhattacharjya, Sunnyvale, CA (US);
Joseph Shu, San Jose, CA (US);
Seiko Epson Corporation, Tokyo, JP;
Abstract
Dither thresholds are assigned one after the other to matrix locations in the process of generating a dither matrix used for printer half-toning. The matrix location to be assigned the next threshold is chosen by locating the tightest cluster or largest void in the dot pattern that will result from the gray level with which the threshold being assigned is associated. Measures of cluster tightness for low-range and high-range thresholds are based on the areas of Voronoi partitions associated with respective candidate locations. For mid-range thresholds, a Gaussian-filter output is used as the measure. In both cases, ties between candidate locations are resolved by applying a further criterion, which depends on the candidate locations' proximities to locations assigned thresholds the same as the one being assigned or differing from it by only one. If a tie still remains, the matrix is divided into blocks, a determination is made of the number of dots that will result from various blocks' thresholds at the gray level associated with the threshold being assigned, and a choice is made among the remaining candidate locations in accordance with the numbers of dots determined for the respective blocks in which they are located.