| 摘要 |
PURPOSE:To decrease greatly the memory capacity compared with conventional values and to attain the reduction of cost with a still picture transmitter, by comparing the high-order bits of key gradation data with each other and detecting a change part of the picture of this time against the picture of the preceding time. CONSTITUTION:The picture signals of a monitored picture photographed by a TV camera 1 are fetched by a picture processing circuit 10 and written successively on a picture storage area of this time of a picture data memory 3 after A/D conversion. Then the monitor picture is divided into (4X4) segments S11-S44, and the gradation data on specific points O11-O44 are outputted as the key gradation data. The high-order bits of said key data are sent properly to the memory 3 and a transmission control circuit 11. The circuit 11 compares the high-order bits of the key gradation data on the picture of the preceding time with those of the key gradation data on the picture of this time. Thus the circuit 11 detects a change part of the picture and also extracts the picture data on this change part to output it as the transmission data.
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