The equivalence of Fourier-based and Wasserstein metrics on imaging problems
Gennaro Auricchio, Andrea Codegoni, Stefano Gualandi, Giuseppe Toscani, Marco Veneroni · Rendiconti Lincei Matematica e Applicazioni · 2020
We investigate properties of some extensions of a class of Fourier-based probability metrics, originally introduced to study convergence to equilibrium for the solution to the spatially homogeneous Boltzmann equation. At di¤erence with the original one, the new Fourier-based metrics are well-defined also for probability distributions with di¤erent centers of mass, and for discrete probability measures supported over a regular grid. Among other properties, it is shown that, in the discrete setting, these new Fourier-based metrics are equivalent either to the Euclidean–Wasserstein distance W_2 , or to the Kantorovich–Wasserstein distance W_1 , with explicit constants of equivalence. Numerical results then show that in benchmark problems of image processing, Fourier metrics provide a better runtime with respect to Wasserstein ones.