US Patent 7505612 Image construction method, fingerprint image construction apparatus, and program

When slide operation of a finger on a sweep type fingerprint sensor is not constant, it is difficult to construct a general image of a fingerprint. An inspection region, which is used to find a difference between a latest partial image read by a sweep type fingerprint sensor and an already acquired partial image, is set in the already acquired partial image along a displacement direction of a plurality of consecutive already acquired partial images. A retrieval range for a position of superposition of the latest partial image on the already acquired partial image is set on the basis of a position of the inspection region. Displacement of the latest partial image with respect to the already acquired partial image is caused in the retrieval range and a difference between the already acquired partial image and the latest partial image concerning the inspection region is found every displacement. In addition, displacement of the latest partial image corresponding to a minimum difference quantity among the found difference quantities is determined as the position of superposition, and the latest partial image is disposed in the position of superposition with respect to the already acquired partial image and the latest partial image is stored.