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Compression Name CCITT T.4
Other names CCITT Group 3
Identifier(s) PUID:  x-cmp/14
Description Officially known as CCITT T.4, Group 3 is a compression algorithm developed by the International Telegraph and Telephone Consultative Committee in 1985 for encoding and compressing 1-bit (monochrome) image data. Its primary use has been in fax transmission, and it is optimised for scanned printed or handwritten documents. Group 3 is a lossless algorithm, of which two forms exist: one-dimensional (which is a modified version of Huffman encoding) and two-dimensional, which offers superior compression rates. Due to its origin as a data transmission protocol, Group 3 encoding incorporates error detection codes. Group 3 compression is most commonly used in the TIFF file format.
Lossiness Lossless
Released 01 Jan 1985
Developed by International Telecommunication Union
Supported by
Documentation CCITT Blue Book, 1989, Volume VII, Fascicle VII.3: Terminal equipment and protocols for telematic services, recommendations T.0 - T.63
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