1. An image processing device, comprising: a contrast correcting unit configured to correct contrast of a plurality of input images; a feature detecting unit configured to detect a predetermined feature from the plurality of input images that are corrected by the contrast correcting unit; a depth map generating unit configured to generate a depth map based on a detection result from the feature detecting unit, wherein the feature detecting unit comprises a feature value detecting unit configured to detect a predetermined feature value from the plurality of input images, the image processing device further comprises a depth estimating unit configured to estimate a depth of a target pixel by means of the feature value detected by the feature value detecting unit, the depth at the target pixel being information representing which of the plurality of input images is in focus at the target pixel, and the depth map generating unit generates the depth map based on an estimation result from the depth estimating unit.