초록 ▼

Encoding and decoding between fixed and variable length binary codes to achieve data compression and decompression is performed without the necessity for storing the entire variable length minimum redundancy code format. In encoding, data is compressed by generating a minimum redundancy code of a bi

Encoding and decoding between fixed and variable length binary codes to achieve data compression and decompression is performed without the necessity for storing the entire variable length minimum redundancy code format. In encoding, data is compressed by generating a minimum redundancy code of a bit length and binary value inversely proportional to the probability of an occurrence of the fixed length binary message from which the minimum redundancy binary code symbol is derived. The compressed binary symbols are transmitted or stored in serial form. In decoding, data is decompressed by sequentially generating portions of threshold binary symbols in the minimum redundancy code and comparing with corresponding portions of a received or recovered binary symbol as it is shifted through the decoder. The comparison results define the bit length and binary value of the binary symbol without the necessity for ever storing the binary symbol in its entirety. This technique of compression and decompression is especially useful for the transmission or storage of digital image data where the probability of occurrence of particular data information is predictable.

대표청구항 ▼

A method transferring image information from a video scanner which produces video signals having a predetermined number of bit positions and corresponding to levels of contraSt of image information utilizing an encoder and a decoder comprising: assigning each permutation of bit arrangement of said v

A method transferring image information from a video scanner which produces video signals having a predetermined number of bit positions and corresponding to levels of contraSt of image information utilizing an encoder and a decoder comprising: assigning each permutation of bit arrangement of said video signals a rank order of probability, encoding each of said video signals by generating in association therewith a binary symbol of variable length according to the rank order of probability of occurrence of the video signal associated therewith from a symbol format of minimum redundancy by generating a threshold value which is the cumulation of numbers of symbols of each smaller bit length multiplied by decreasing powers of two with increasing bit length and by generating a residual value indicative of a relative position of probability within symbols of like bit length, serially communicating said binary symbols to said decoder, decoding each of said encoded binary symbols by regenerating the threshold prefix value in said decoder for each encoded binary symbol, subtracting said threshold prefix value therefrom to isolate the associated residual value, and calculating the threshold order of probability of binary signals of like symbol length from said regenerated threshold, and combining said threshold order of probability with said residual value to identify the video signal used to generate said binary symbol.