BINARY IMAGE CODER AND BINARY IMAGE DECODER

摘要

PURPOSE: To attain a high coding efficiency by obtaining a coded picture element and a context through the extraction of the picture element based on template from binary image data read in a line memory and setting an accurate augend depending on an incident probability of a symbol. ;CONSTITUTION: Binary image data by three lines are read in a line memory 501 and subject to picture element processing 502 based on a template to obtain a context CX and a coding noted picture element PIX. Number of times of appearance of the CX and the count of the picture elements PIX are stored in an SRAM 504 by count processing 503. A variable conversion processing 505 obtains a symbol appearance probability based on the values and the probability is converted into a product of primes by a prime conversion table 506 and its power is stored in the SRAM. A register arithmetic processing 508 multiplies the appearance probability in the SRAM with a range of the probability. An augend is expressed as a product of primes and sets of power are added when it is updated. A code when an incident probability deteriorated symbol is generated for a reference code and compared with coded data to discriminate whether the decoded symbol is a superior symbol or an inferior symbol and decode.;COPYRIGHT: (C)1996,JPO