IMAGE SIGNAL FEATURE QUANTITY PROCESSING UNIT AND IMAGE SIGNAL CODER

摘要

PURPOSE: To provide the image signal feature quantity processing unit and the image signal coder by improving image quality under a prescribed information amount so as to reduce visual deterioration. CONSTITUTION: Image data of an image signal are divided into small blocks by a small block division section 402 and a feature quantity extract section 409 obtains plural characteristic quantities for each block. Then a feature quantity space division area in existence in the vicinity of a feature vector comprising plural feature amounts is sought by a vicinity division area discrimination section 411 and a feature quantity space vector dependence degree calculation section 414 calculates the degree of dependence. A quantization control parameter based on the proper visual characteristic is calculated based on the degree of dependence and the visual sensitivity allocated to the division area. Thus, the rapid change in the quantization control parameter is suppressed regardless of the presence of a limit of the feature quantity and more proper quantization control is conducted, resulting that the image quality is enhanced under a prescribed information amount thereby reducing visual deterioration.