PURPOSE: To improve an SN ratio by using an average value or a deviation from the average as index information for classifying blocks and selecting a code book in each class.
CONSTITUTION: A digitized image signal is inputted from an input terminal to a scanning conversion circuit 2 and divided into small blocks. A forecasting value (an output value from a frame memory 12) is subtracted from each divided signal and only a signal in a dynamic range is outputted from an effective block deciding circuit 4 to an average value separating circuit 5. After separating the average value in the circuit 5, deviation information such as a standard deviation or variance is obtained by a deviation normalizing circuit 6. An encoder 7 outputs index information for selecting any one of n code books for vector quantization on the basis of the deviation information.
KURODA HIDEO
HASHIMOTO HIDEO
| JPS60130926A | 1985-07-12 |