1. An image processing apparatus comprising: an acquisition unit configured to acquire an image; a detection unit configured to detect each object region from the image acquired by said acquisition unit; a luminance distribution calculation unit configured to calculate a luminance distribution for each object region detected by said detection unit; a representative luminance value calculation unit configured to calculate a representative luminance value for each object region detected by said detection unit; and a determination unit configured to determine tone characteristics for each object region based on the luminance distribution for each object region calculated by said luminance distribution calculation unit and a relationship between the representative luminance values for the respective object regions calculated by said representative luminance value calculation unit.