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:
Sep. 29, 1998
Filed:
Feb. 01, 1995
Dainippon Screen Mfg. Co., Ltd., Kyoto, JP;
Abstract
A threshold matrix is divided into a plurality of sub-matrices Tij of an equal size. The difference between a plurality of threshold data included in each sub-matrix Tij is set to a specific value while the plurality of threshold data are arranged at random in each sub-matrix Tij. In case that each sub-matrix is a 2.times.2 arrangement, there are eight diagonal patterns where two relatively small threshold data are arranged diagonally while two relatively large threshold data are also arranged diagonally. A threshold matrix having the sufficiently high spatial frequency and allowing smooth tone reproduction can be prepared by selecting one of the eight diagonal patterns at random. A plurality of threshold matrices for respective color separations thus prepared will reduce the graininess and muddiness of colors in a reproduced color image. A plurality of threshold matrices can be produced from one original threshold matrix by extracting part of the threshold matrix.