Implementation of Deformable Filter Banks
This paper describes e cient schemes for the computation of a large number of di erentely scaled/oriented ltered versions of an image. We generalize the well-known steerable/scalable ("deformable") lter bank structure by imposing X-Y separability on the basis lters. This systems, designed by an iterative projections technique, achieve substantial reduction of the computational cost. To reduce the memory requirement, we adopt a multirate implementation. The resulting structure, however, is not shift-invariant it gives raise to "aliasing". We introduce a design criterion for multirate deformable structures that jointly controls the approximation error and the shift-variance.