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.

Date of Patent:
Mar. 13, 2001

Filed:

Mar. 19, 1998
Applicant:
Inventors:

Nobuhito Matsushiro, Tokyo, JP;

Kazuyo Kurabayashi, Tokyo, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H04N 1/403 ; H04N 1/405 ; H04N 1/40 ; G06K 9/34 ; G06K 9/38 ;
U.S. Cl.
CPC ...
H04N 1/403 ; H04N 1/405 ; H04N 1/40 ; G06K 9/34 ; G06K 9/38 ;
Abstract

A multi-level input image is divided into blocks, each of which is quantized to a bi-level output block. A single quantization error value is calculated for each block, and distributed over neighboring blocks that have not yet been processed. Blocks containing abrupt changes in image content are preferably converted by comparing each picture element individually with a threshold value. Blocks not containing abrupt changes are preferably quantized by comparing the average value of the block with multiple threshold values to determine a multi-level block output value, from which a predetermined pattern of bi-level picture elements is generated.


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