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. 18, 1999
Filed:
Apr. 24, 1997
Osamu Shimazaki, Kanagawa-ken, JP;
Fuji Photo Film Co., Ltd., Kanagawa-ken, JP;
Abstract
A multi-valued image signal I(x,y) is compared with a threshold signal TH by a comparator to produce a binary image signal P(x,y), and an error signal E(x,y) is determined from the binary image signal P(x,y) and the multi-valued image signal I(x,y). Error diffusion coefficients W1(k,l), W2(k,l), W3(k,l) are prepared in advance which correspond respectively to the filter characteristics of a 'Jarvis-type filter', an 'elongate rectangular filter', and a 'Floyd-type filter'. A mixing ratio setting circuit determines mixing ratios t1(I.sub.0), t2(I.sub.0), t3(I.sub.0) depending on the multi-valued image signal. The mixing ratios t1(I.sub.0), t2(I.sub.0), t3(I.sub.0) are accumulated and added to the error diffusion coefficients W1(k,l), W2(k,l), W3(k,l), and an error signal E(x-k,y-l) and an error diffusion coefficient W(k,l,I.sub.0) are accumulated and added, producing a diffusion error signal .DELTA.E(x,y). The diffusion error signal .DELTA.E(x,y) is added to the multi-valued image signal I.sub.0 (x,y), producing-a corrected multi-valued image signal I(x,y), which is then compared with the threshold signal TH by the comparator to generate a binary image signal P(x,y).