1. An image processing apparatus, comprising: an extraction unit configured to extract a feature point from an input image including an image region in which depth values of pixels change consecutively; a generation unit configured to, a normalization transformation being a transformation that normalizes depth values of pixels of a vicinity of the feature point with respect to a region of at least a portion of the input image, generate an image for a feature amount calculation by performing the normalization transformation on a pixel position of the feature point; and a calculation unit configured to calculate a feature amount from the image for the feature amount calculation generated by the generation unit.