04205341 is referenced by 60 patents and cites 7 patents.

A frame of a gray-scaled picture is divided into blocks, in each of which the mean luminance of picture elements is used as a threshold value for comparison with each picture element signal to classify it into 0 or 1 according to its magnitude to provide a resolution component. From the resolution component and each picture element signal in the block are calculated two gray components; the resolution component and the two gray components are used as coded outputs for each block. The size of each block is changed in accordance with the property of the picture in the portion corresponding to the block.

Title
Picture signal coding apparatus
Application Number
5/960541
Publication Number
4205341
Application Date
November 14, 1978
Publication Date
May 27, 1980
Inventor
Naohiko Kamae
Tokyo
JP
Katsusuke Hoshida
Hoya
JP
Tomio Kishimoto
Yokosuka
JP
Eiji Mitsuya
Yokohama
JP
Agent
Pollock Vande Sande and Priddy
Assignee
Nippon Telegraph and Telephone Public Corporation
JP
IPC
H04N 7/12
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