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:
Aug. 19, 2003
Filed:
May. 21, 1999
Michiyuki Suzuki, Yamatokoriyama, JP;
Yoshinori Hayashi, Kyoto, JP;
Sharp Kabushiki Kaisha, Osaka, JP;
Abstract
An object of the present invention is to avoid such a problem that white dropouts and the Moire phenomenon occur in a filter-processed image. A filter unit employed in an image processing apparatus provided within a copying machine first selects as a pixel of interest any one of a plurality of reversed density pixels which constitute an image to be processed. Next, the filter unit uses density of this interest pixel before being corrected, density of pixels located at peripheral portions of this interest pixel, and a predetermined filter coefficient so as to calculate a weighted average value for each of the density. Finally, the filter unit compares the density of this interest pixel before being corrected with the weighted average values to output as a corrected density of this interest pixel, such a value approximated to a density equivalent to a black level. Furthermore, the filter unit compares the density of the interest pixel before being corrected with the predetermined reference density and, only when the density before being corrected is less than the reference density, it outputs the above-described weighted average value as the corrected density of this interest pixel irrespect to such a large/small relationship between the density before being corrected and the weighted average value.