1. An image processing method for reducing a ringing artifact in an input image, said image processing method comprising: selecting, from among a plurality of pixels included in the input image, a candidate for a noise pixel included in the ringing artifact, using luminance values of the plurality of pixels; judging whether or not the candidate selected in said selecting is the noise pixel based on whether or not a chrominance value of the candidate is included in a chrominance range corresponding to a comparison target region which is a part of the input image; and filtering the noise pixel which has been judged in said judging.