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:
Feb. 28, 1995
Filed:
Oct. 01, 1992
Seita Shono, Warabi, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
An image processing apparatus, which stochastically binary-converts lower-bit data of a pixel of interest to improve image quality in a highlight portion, as well as in a low-density portion, is provided. In an image processing apparatus for quantizing multi-value image data to binary data, multi-value image data of a pixel of interest is divided into upper- and lower-bit data by a calculator (24). The lower-bit data is binary-converted by a comparator (25) using a normalized uniform random number generated by a random number generator (26) as a threshold value. The binary-converted data is added to the upper-bit data of the image signal of the pixel of interest by an adder (22), and the sum data is binary-converted by a comparator (18) using one of a plurality of weighted average values of a plurality of pixels near the pixel of interest, which values are calculated by a calculator (600), on the basis of binary data of pixels, which have already been binary-converted before the pixel of interest. At this time, the density is preserved by distributing a density error generated upon binary conversion to non-binary-converted pixels near the pixel of interest by a circuit including a subtracter (17), an adder (22), and the like.