Vision and Robotics Seminar
Nathan Cahill
The Wolfson Medical Vision Laboratory
University of Oxford
will speak on
Deformable registration in medical imaging
Abstract:
In medical imaging, it is frequently useful to register or align images in order to fuse
complementary information or to make quantitative assessments. In many situations (for example,
3D magnetic resonance imaging of the breast), the anatomical object being imaged undergoes a
nonrigid deformation between successive images. We describe how the underlying nonrigid deformation
can be recovered via a functional minimization process. Using the calculus of variations, the solution
of the functional minimization problem is transformed into the stationary solution of a system of
partial differential equations (the Euler-Lagrange equations). We then show how different types of
regularization (homogeneous, variable isotropic, and anisotropic), common in the fields of diffusion
filtering and optic flow, can be generalized to the various standard regularizers (elastic, fluid,
and curvature) used in nonparametric image registration. We finally show how the resulting semilinear/nonlinear
Euler-Lagrange equations can be discretized and solved quickly using Fourier methods or multigrid techniques,
yielding a class of computationally tractable algorithms for deformable image registration.
The lecture will take place in the Lecture Hall, Room 1, Ziskind Building
on Thursday, Oct 18, 2007
noon - 13:00