| 摘要 |
PURPOSE: To further reduce the number of bits necessary for indicating a picture or an image without deteriorating a picture quality so much by providing an evaluating circuit which receives a masking function value, and decides a control signal value for a present picture element according to it. CONSTITUTION: A transmitter used for a predictive encoding system is provided with a TV camera 1 which converts an image P into an analog video signal. An A/D converted pixel value is impressed to a predictive encoding circuit 3, and the pixel value and a predicted value from a predicting circuit 10 are applied to a difference generator 4. An obtained difference value is converted into a predicted error by a quantizer 5, and impressed to a switching element 6 and an inverse quantizer 7. This predicted error is converted into an auxiliary predicted error by the inverse quantizer 7, impressed to a switching element 8 controlled by a control signal outputted by an evaluating circuit 11, and a corrected auxiliary predicted value is generated. A masking function circuit 10 calculates a masking function value from the predicted value and the corrected auxiliary predicted value, and supplies it to the evaluating circuit 11. The switching element 6 receives the output of the evaluating circuit 11, and transmits the predicted error to a variable length encoder 12. |
