Patent ID: 7567299

Claim:
A frame-cyclic noise reduction method employed for an image display device in which one field is divided into a plurality of sub-fields, each sub-field having a predetermined weight of luminance, and in which turned-on sub-fields are properly combined to provide an image with gradation, the frame-cyclic noise reduction method comprising: that is, where sub-field fuzziness becomes worse; and controlling a cyclic amount for the area in which the sub-field fuzziness becomes worse to be different from a cyclic amount for other areas, wherein a movement amount is detected according to a differential signal calculated as a difference between a current-frame image signal and a one-frame-before image signal, and the cyclic amount is decreased as the movement amount increases in the area where the sub-field fuzziness becomes worse or in the other areas, and wherein a cyclic amount corresponding to a movement amount in the area where the sub-field fuzziness becomes worse is determined to be equal to, or to be smaller than the cyclic amount for areas other than the area where the sub-field fuzziness becomes worse.