| 摘要 |
PURPOSE:To satisfactorily restore the block picture of small AC electric power by using a threshold which is decided in accordance with the distribution of the coefficient values of respective blocks in one picture in the case of reducing the information quantity of converted and encoded coefficient values. CONSTITUTION:The information quantity of the coefficient values in a sine conversion circuit 2 is reduced in a thresholding circuit 3, and a coding circuit 5 converts the values into code signals. A buffer memory 6 outputs data of a prescribed rate corresponding to the transmission rate of the transmission line of the code signals in the circuit 5. The memory 6 decides a prescribed value (x) at every one picture, and it is given to a multiplication circuit 10 in the circuit 3. A maximum value detection circuit 9 detects the maximum value of the coefficient values from the circuit 2 and the circuit 10 multiplies it with the value (x), whereby a subtraction circuit 8 subtracts the signal from the coefficient values of the circuit 2 as the threshold. Thus, the picture of small AC electric power can satisfactorily be restored. |
