  We present a method for nonrigid registration of 2-D geometric shapes. Our
contribution is twofold. First, we extend the classic chamfer-matching energy
to a variational functional. Secondly, we introduce a meshless deformation
model that can handle significant high-curvature deformations. We represent 2-D
shapes implicitly using distance transforms, and registration error is defined
based on the shape contours' mutual distances. In addition, we model global
shape deformation as an approximation blended from local deformation fields
using partition-of-unity. The global deformation field is regularized by
penalizing inconsistencies between local fields. The representation can be made
adaptive to shape's contour, leading to registration that is both flexible and
efficient. Finally, registration is achieved by minimizing a variational
chamfer-energy functional combined with the consistency regularizer. We
demonstrate the effectiveness of our method on a number of experiments.
