SYSTEM FOR COMPRESSING IMAGE SIGNAL BAND

Japanese Patent JPH01183978

A

PURPOSE:To reduce the deterioration of picture quality caused by transition between modes of which picture quality difference is big by comparing a past mode decision result and a fixed mode pattern and prohibiting or forcing the selection of the fixed mode pattern when they coincide each other. CONSTITUTION:The mode compressibility of the mode 1 is '1' and that of the mode 2 is 1/4. Then, the mode 2 uses interpolation in a field. The thinning and the interpolation of the mode 2 are executed for an image signal 50 inputted from an input terminal by a mode 2 thinning and interpolation circuit 1, the output of it is inputted to a difference circuit 2, the difference between an interpolation signal and an original signal is calculated, an interpolation error S every block being a total sum in the block of the absolute value of a difference signal is calculated and the error S is outputted as an interpolation error signal 51. A mode pattern comparison circuit 8 makes a mode pattern signal 57 and the mode signal 53 of one field before to be as input, refers the mode decision result until past three field before, decides whether the mode is forcibly made to be the mode 1 or the mode 2 and outputs a mode pattern comparison decision signal 52.

ASHIBE MINORU
TANIMOTO MASAYUKI

JP893388A

July 21, 1989

January 18, 1988

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NEC CORP
TANIMOTO MASAYUKI

H04N19/00; H04N19/132; H04N19/134; H04N19/172; H04N19/176; H04N19/196; H04N19/423; H04N19/59; H04N19/65; H04N19/85; (IPC1-7): H04N7/13

JPS61140290A

1986-06-27

Uchihara Shin

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