ACHROMATIC PROCESSING METHOD FOR IMAGE DATA

PURPOSE:To eliminate the leakage of a sample color at a boundary part of synthesization and to obtain a soft chromakey synthetic screen with high quality by applying the continuous achromatic processing to the mixture component of the sample color and another color. CONSTITUTION:The foreground picture data are fetched into an image memory 1 and the hue data, etc., on the images are read out of the memory 1. A CPU 4 generates a parameter necessary for the achromatic processing conversion of a hue range (processing range) where the achromatic processing is carried out based on the read data. The parameter is sent to a conversion processing part 2. The part 2 performs the achromatic processing of the foreground picture data read out of the memory 1 through an arithmetic circuit based on the parameter received from the CPU 4 and a look-up table. Thus the automatic ground picture data are obtained. The processing range of the part 2 is set by the CPU 4 with software in accordance with the hue distribution of the mixed color set at the boundary part of different colors and therefore never limited by the shape and the size of the processing.