1. An image processing apparatus in which luminance values of an input image are converted for output, comprising: a first image information extracting unit configured to extract first image information from a first image region including a target pixel; a first conversion characteristics calculating unit configured to calculate a first conversion characteristic from the first image information; a second image information extracting unit configured to extract second image information from a second image region including the first image region; a second conversion characteristics calculating unit configured to calculate a second conversion characteristic from the second image information; a weighted coefficient calculating unit configured to calculate a weighted coefficient; and a third conversion characteristics calculating unit configured to calculate a third conversion characteristic for converting a luminance value of the target pixel, using the first conversion characteristic, the second conversion characteristic, and the weighted coefficient, wherein the luminance value of the target pixel is converted and outputted based on the third conversion characteristic.