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:
May. 28, 1991

Filed:

Mar. 10, 1989
Applicant:
Inventors:

John M Walsh, Los Gatos, CA (US);

David M Ott, Alameda, CA (US);

Assignee:
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G06K / ;
U.S. Cl.
CPC ...
382 56 ; 358452 ; 382 61 ; 382 57 ;
Abstract

A system for electronically storing revisions or modifications to documents which are already electronically stored in unrevised or unmodified form. The system compares, at the pixel-by-pixel level, a modified document bit map with a stored document bit map and determines from the differences between the two bit maps, at the pixel-by-pixel level, which differences are significant and which are insignificant. A revised document bit map is then formed from the portions of the stored-document bit map exhibiting no significant bit map differences and the significant differences bit map. The result is a revised document bit map in which no unnecessary changes have been introduced into the initial stored-document bit map. The system also includes steps for defining, on a pixel-by-pixel basis, a significant region bit map from the significant difference bit map and for forming the revised document bit map using the significant region bit map.


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