1. An image processing apparatus, comprising: detecting means configured to detect a target object image region from a first image, the detecting means including: generating means configured to generate images having scale coefficients differing from scale coefficients of the first image; extracting means configured to extract feature points from the generated images; calculating means configured to calculate feature values for the feature points by filtering the feature points using a predetermined filter, the detecting means detecting the target object by substituting the feature values into a classifier; setting means configured to set the target object image region as a first region and a remaining region of the first image as a second region, based on a parameter applicable to a target object within the target object image region; removing means configured to remove one of the first region or the second region from the first image; and generating means configured to generate a second image by superimposing the removed region on a third image.