An Accurate Algorithm for Fast Frequency Warping

In this work we present a fast and accurate algorithm to compute frequency warping of arbitrary shaped maps. In contrast to the common Laguerre approach, frequency warping is represented by a matrix of truncated finite dimensions. The transformation matrix is decomposed in two additive terms: the first term represents its nonuniform Fourier transform approximation while the second term is imposed for aliasing suppression. Both matrices are approximated with a least square approach according to a suitable set of vectors. The cardinality of this set is shown to be nearly proportional to the logarithm of the matrix dimension. Finally, trade-off aspects between algorithm complexity and performance are discussed.