An apparatus includes (a) an image processor which (i) calculates a similarity between first image data of a first partial region in object image data and reference image data, with respect to each pair of a second partial region of the first image data and a third partial region of the reference image data that correspond to each other, (ii) calculates a statistic of a plurality of the calculated similarities, with respect to a plurality of the image pairs, and (iii) recognizes, as a position of an object region in the object image data, a position of the first partial region in the object image data, which has the highest statistic of a plurality of the calculated statistics, and (b) an exposure unit which exposes a substrate to a pattern based on the position of the object region recognized by the image processor.