| 摘要 |
PURPOSE:To transmit picture information so as not to outstand the deterioration in visual picture quality by deciding a transmission form used for the transmission according to a threshold set based on the visual characteristic. CONSTITUTION:The respective outputs yn-yn+3 of a shift register 33 are supplied to an adder 40, in the adder 40, the sum of the levels of a luminance signal for an unit block is calculated and the output of the adder 40 is multiplied by a constant K preset in a multiplier 41, thereby, the result is supplied to a comparator 37 as a threshold. The threshold used during the discrimination of a transmission mode is changed according to the level of the inputted luminance signal, thereby, the visual characteristic of a human being is taken into consideration even in the picture of low luminance signal level and the transmission band of a video signal is compressed and transmitted so as not to outstand the deterioration in the visual picture quality.
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