Abstract:
A fully automated, non-rigid image registration algorithm is presented. The
deformation field is found by minimizing a suitable measure subject to a
curvature based constraint. It is a well-known fact that non-rigid image
registration techniques may converge poorly if the initial position is off by
too much. A common approach to address this problem is to perform a time
consuming rigid pre-registration step. In this paper we show that the new
curvature registration not only produces accurate and smooth solutions
but also allows for an automatic rigid alignment. Thus, in contrast to other
popular registration schemes, the new method no longer requires a
pre-registration step. Furthermore, we present an implementation of the new
scheme based on the numerical solution of the underlying Euler-Lagrange
equations. The real discrete cosine transform is the backbone of our
implementation and leads to a stable and fast O(N log N) algorithm,
where N denotes the number of voxels. Finally, we report on some
numerical test runs.