James A Kenemuth

US Patent:

45162468, May 7, 1985

Filed:

Feb 26, 1982

Appl. No.:

6/352681

Inventors:

James A. Kenemuth - Palo Alto CA

Assignee:

Prentice Corporation - Sunnyvale CA

International Classification:

H04N 712

US Classification:

375 37

Abstract:

A character base input data stream is encoded in compressed form by using a histogram of a sample of the data stream to determine the frequency of appearance of characters in the stream. A code for a character M+1 is generated in an encoder (112) to be of a length which is an inverse function of the frequency of appearance of character M+1 in the preceding M characters in the sample. Decoding can be achieved by forming a comparable sample window in a decoder (118) to which is applied an estimated index of the incoming character being decoded.