Mixture of Kernels and Iterated Semidirect Product of Diffeomorphisms   Groups
  In the framework of large deformation diffeomorphic metric mapping (LDDMM), we develop a multi-scale theory for the diffeomorphism group based on previous works. The purpose of the paper is (1) to develop in details a variational approach for multi-scale analysis of diffeomorphisms, (2) to generalise to several scales the semidirect product representation and (3) to illustrate the resulting diffeomorphic decomposition on synthetic and real images. We also show that the approaches presented in other papers and the mixture of kernels are equivalent. 
Martins Bruveris and Laurent Risser and Fran\c{c}ois-Xavier Vialard
math.NA math.FA