A verification apparatus reads an image of a printed sheet using a plurality of imaging units to obtain image data. The verification apparatus extracts feature points of the obtained image data and determines whether a feature point of first image data obtained by a first imaging unit should be a feature point of second image data that should be obtained by another imaging unit. If so, the verification apparatus converts coordinates of the feature point of the second image data to a coordinate system of the first imaging unit, calculates a geometrical conversion parameter from the coordinates of the converted feature point and coordinates of feature points other than the converted feature point, and aligns the image data of the printed sheet and a correct image based on the geometrical conversion parameter.