Position Alignment Method, Position Alignment Device, and Program

A position alignment device characterized by comprising:

• a work memory;
• and
• a position alignment unit that aligns one input image and another image with each other using the work memory,
• wherein the position alignment unit
• aligns, using as a reference a group of some points in a first set of points extracted from an object appearing in the one image and a group of some points in a second set of points extracted from an object appearing in the other image, the second set of points with respect to the first set of points, and
• aligns, using as a reference all points in the first set of points and all points in the aligned second set of points, the second set of points with respect to the first set of points.