| 摘要 |
PURPOSE:To compress transmitted data by providing a difference circuit which outputs the difference in level between a past picture signal and a current picture signal, an area specifying circuit which discriminates whether the difference is larger than a specific value or not and outputs an encoding indication signal for indicating an area on one screen to be encoded, and an encoding circuit. CONSTITUTION:The difference between a picture element signal S1 inputted block by block and a prediction signal S2 from a frame memory 4 is calculated by the difference circuit 1, whose output is quantized by a quantizer 2 to output a quantized signal S3. This quantized signal S3 is inputted to an adding circuit 3, feature picture element detecting circuit 5, and delay circuit 8. The feature picture element detecting circuit 5 discriminates whether the quantized signal is at a level ''0'' or not and inputs the result to an effective/ineffective block discriminating circuit 6 as a signal S4, and the result is inputted as a signal S5 to the area specifying circuit 7 and a multiplex circuit 10. The area specifying circuit 7 detects maximum and minimum cooridinates of an effective block on the basis of the signal S5, and outputs the coordinates as a signal S8 and also input an indication signal S9 indicating encoding to the encoding circuit 11. |
