1. An image processing apparatus comprising; a receiving unit configured to receive an input image; a reduction unit configured to execute reduction processing of the input image to generate a plurality of reduced images that are reduced with respective different reduction degrees; an extraction unit configured to extract a feature point from the input image and the reduced image; a parameter acquisition unit configured to acquire a normalization parameter from an image higher in reduction degree than an image from which the feature point is extracted; and a normalization unit configured to normalize pixel values of an area containing an area for calculating a local feature amount concerning the feature point based on the normalization parameter, wherein an area to be normalized is an area in an image conforming to the feature point from which the extraction unit extracts the feature point.