An apparatus includes a resolving unit configured to resolve input image data into image data for each frequency band, an acquisition unit configured to acquire skewness corresponding to the resolved image data resolved by the resolving unit, wherein the skewness is acquired from a histogram corresponding to each of the resolved image data, and an adjustment unit configured to determine image data to be processed, out of the resolved image data based on the acquired skewness acquired and perform gain adjustment on the determined image data.