1. A method for registering a first image to a second image using a similarity transformation, the first image including a first plurality of pixels mapped to a set of first image coordinates and the second image including a second plurality of pixels mapped to a set of second image coordinates, the method comprising the steps of: a) determining the first image coordinates of a first reference point and a second reference point in the first image; b) determining the second image coordinates of the first reference point and the second reference point in the second image; c) performing a Cartesian translation of the set of second image coordinates such that the second image coordinates of the first reference point match the first image coordinates of the first reference point; and d) performing a similarity transformation of the translated set of second image coordinates to scale the second image coordinates and rotate the second image coordinates about the first reference point such that the second image coordinates of the second reference point match the first image coordinates of the second reference point.