Robust point correspondence applied to two and three-dimensional image registration

Accurate and robust correspondence calculations are very important in many medical and biological applications. Often, the correspondence calculation forms part of a rigid registration algorithm, but accurate correspondences are especially important for elastic registration algorithms and for quanti fying changes over time. In this paper, a new correspondence calculation al gorithm, CSM (Correspondence by Sensitivity to Movement), is described. A r obust corresponding point is calculated by determining the sensitivity of a correspondence to movement of the point being matched. If the corresponden ce is reliable, a perturbation in the position of this point should not res ult in a large movement of the correspondence. A measure of reliability is also calculated. This correspondence calculation method is independent of t he registration transformation and has been incorporated into both a 2D ela stic registration algorithm for warping serial sections and a 3D rigid regi stration algorithm for registering pre and postoperative facial range scans . These applications use different methods for calculating the registration transformation and accurate rigid and elastic alignment of images has been achieved with the CSM method. It is expected that this method will be appl icable to many different applications and that good results would be achiev ed if it were to be inserted into other methods for calculating a registrat ion transformation from correspondences.