A feature point is extracted from an input image including an image region for which depth values of pixels change consecutively. 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 is set as a normalization transformation, and an image for a feature amount calculation is generated by performing the normalization transformation on a pixel position of the feature point. A feature amount is calculated from the image for the feature amount calculation.