GRADATION LOWERING PROCESSING METHOD, PROCESSOR THEREFOR INTEGRATED CIRCUIT FOR GRADATION LOWERING PROCESSING, AND COMPUTER-READABLE RECORDING MEDIUM RECORDED WITH GRADATION LOWERING PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a gradation lowering processing method and a gradation lowering processor, which can suppress a memory required for a processing more than usual, by executing a quantized error diffusion processing prior to a filter processing. SOLUTION: Input gradation data of a picture element, which is outputted from an input buffer 1, is inputted to an error diffusion processing means 2. The error diffusion processing means 2 outputs gradation data where the error of the picture element is diffused. Reproduced gradation data is inputted to a sharpening processing means 8 with input gradation data and corrected gradation data on the picture element is outputted. Namely, the quantized error diffusion processing and the sharpening processing (filter processing) are executed prior to the quantization processing. A memory for storing gradation data required for the filter processing and a memory storing gradation data required for the quantized error diffusion processing can be shared. The total capacity of the memory required for the gradation lowering processing can be reduced.