An image processing method and apparatus RGB luminance data for target pixel P(n) and adjacent pixels P(n−1) and P(n+1) to one set of luminance data L(i) and two sets of color difference data Cr(i) and Cb(i). Intermediate values Crm(n) and Cbm(n) for the color difference data are calculated for the pixels P(n−1), P(n). A change in the luminance data in the vicinity of the target pixel P(n) is determined. When a predetermined condition is satisfied, the intermediate values replace color difference data Cr′(n) and Cb′(n) for the target pixel P(n). When the predetermined condition is not satisfied, weighted average values of the intermediate values and original color difference values Cr(n) and Cb(n) replace the color difference data for the target pixel P(n). Thereafter, the color difference data for the target pixel P(n) and the luminance data that are not changed are again converted in the RGB color space.