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:
Jan. 10, 1984
Filed:
Aug. 17, 1981
Vinod K Kadakia, Torrance, CA (US);
Glen D Jones, Orange, CA (US);
Xerox Corporation, Stamford, CT (US);
Abstract
A predictor bit pattern comprising selected bits of the current and previous raster scan lines and a method of predicting a plurality of bits per clock are disposed. Generally, a predictor is used prior to the encoding of data to increase the compression. The current bit in a bit stream is compared to the predicted value and a one is output when the two values are not equal. An efficient predictor will reduce the number of ones in a bit stream, which increases the zero run lengths and increases the efficiency of a run length encoding system. The described bit pattern contains bits close to the current bit to efficiently predict text data, bits distant from the current bit to efficiently predict halftone data, and ignores a plurality of intermediate bits to reduce hardware costs. A two step process is also described to allow a plurality of bits to be predicted in parallel. A circuit for performing this process comprises a buffer for storing the previous and current line data, two registers for holding the previous and current line prediction data patterns and two PROMs for performing the two step prediction.