1. An image processing apparatus comprising: a data memory configured to register a set of feature data for each person of a plurality of persons, and to classify the feature data in all the registered sets into a plurality of subsets such that each subset includes a part of the feature data; an extraction unit configured to extract feature data from image data of a person in an obtained image; a selection unit configured to select a subset from the plurality of subsets; and an object recognition unit configured to recognize the person in the obtained image by comparing the feature data included in the subset selected by the selection unit with the feature data extracted by the extraction unit, wherein the object recognition unit gives an order of priority to the feature data of the subset selected by the selection unit, and compares the feature data extracted by the extraction unit with the feature data of the subset selected by the selection unit in the order of priority based on an image sensing mode.