04316222 is referenced by 48 patents and cites 15 patents.

A digital image data compression system which generates a plurality of run length symbols, with each symbol comprising a white portion and a black portion. The white portion may contain up to a specified maximum number of white pixels, while the black portion may contain up to a second specified maximum number of black pixels. A symbol may be composed of a black portion followed by a white portion (a BW type run), or a white portion followed by a black portion (a WB type run). If the second portion of any run length of a particular type run exceeds the maximum number of pixels allowed for that color, that run length is terminated at the maximum number, the corresponding symbol is generated, and a special symbol, indicating a change in the type of run, is inserted. The symbol following the special symbol, which is the opposite type from the original symbol, is generated using the remaining pixels from the last run length and the following run length of the opposite color. The symbols are used to provide address data for memory devices which generate variable length code words that are transmitted to a receiving station and decoded to provide symbols which are used to form a facsimile image.

Title
Method and apparatus for compression and decompression of digital image data
Application Number
6/101347
Publication Number
4316222
Application Date
December 7, 1979
Publication Date
February 16, 1982
Inventor
Ambati Subramaniam
Waterloo
CA
Agent
Jerrold J Litzinger
Albert L Sessler Jr
J T Cavender
Assignee
NCR Canada NCR Canada LTEE
CA
IPC
H04N 1/00
H04N 7/12
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