Facsimile and static presentation processing – Facsimile – Specific signal processing circuitry
Patent
1988-02-04
1989-05-23
Britton, Howard W.
Facsimile and static presentation processing
Facsimile
Specific signal processing circuitry
358133, 358136, 358138, 375 27, 375 33, 375122, H04N 7133, H04N 7137
Patent
active
048335355
ABSTRACT:
An input image signal is divided into blocks each of 8 x 8 pixels, is subjected to cosine transform and is then converted to a signal of a spatial frequency region. After the cosine transform, the data is subjected to subtraction with respect to first to fourth types of data. Data of the same block of the one previous frame is used as the first data to provide a first difference between frames. Data of different blocks in the same frame is used as the second data to provide a second difference within the same frame. The third data is background image data and the fourth data is specific data. The minimum one of the first to fourth difference data is selected, and is then quantized and transmitted. Accordingly, a difference data involving a small amount of information to be transmitted can be selected for each block, thus always realizing a high transmission efficiency irrespective of the degree of image change.
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National Convention Record, 1987, The Institute of Electronics, Information and Communication Engineers, Part 5, K. Dachika, T. Watanabe and F. Sugiyama.
National Convention Record, 1987, The Institute of Electronics, Information and Communication Engineers, Part 5, T. Watanabe et al.
"Cosine Transform Circuit" 1987, National Convention Record of ITEJ 6-14.
Dachiku Kenshi
Fujiwara Hisao
Ozeki Kazuo
Sugiyama Fumio
Watanabe Toshiaki
Britton Howard W.
Kabushiki Kaisha Toshiba
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