A method includes obtaining a first image, obtaining a second image,
determining a deformation field using the first and second images, and
determining a transformation matrix using the deformation field. A
computer product having a set of instruction, an execution of which
causes a process to be performed, the process comprising determining a
deformation field using first and second images, and determining a
transformation matrix using the deformation field. A system includes a
computer-readable medium for storing a first image and a second image,
and a processor configured to determine a deformation field using the
first and second images, and determine a transformation matrix using the
deformation field.