Patent ID: 7102599

Claim:
A method for processing an image signal in which one field period is divided into a plurality of subfields having different relative luminance ratios, and generating a plurality of gradation levels of an image by combining said subfields, the method comprising the steps of: detecting a series of pixels in which the gradation level changes smoothly with respect to the pixel position in said one field period; detecting neighboring two pixels which satisfy first and second predetermined relationships between said neighboring two pixels in the detected series of pixels in at least one subfield of said one field period, said first predetermined relationship being a relationship in which one or more subfields representing a gradation level of one of said neighboring two pixels do not include a subfield with a weight that is the same as a highest weight or second highest weight of one or more subfields representing a gradation level of the other of said neighboring two pixels, and said second predetermined relationship being a relationship in which said one or more subfields representing a gradation level of one of said neighboring two pixels include a subfield with a weight higher than said highest weight or second highest weight of one or more subfields representing a gradation level of the other of said neighboring two pixels; and changing an arrangement of the gradation levels among the detected series of pixels including the detected neighboring two pixels.