2009/01/27 by Matti Lassas. Eero Saksman, Saksman, Matti Lassas. Eero, Samuli Siltanen +1 · 9 citations
Computer Science · Engineering · Mathematics · #42C40 #60F17 #65C20 #FOS: Computer and information sciences #FOS: Mathematics #Image and Signal Denoising Methods #Methodology (stat.ME) #Numerical methods in inverse problems #Probability (math.PR) #Sparse and Compressive Sensing Techniques
paper · pdf · doi:10.48550/arxiv.0901.4220
openalex publication_date 2009/01/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Bayesian solution of an inverse problem for indirect measurement M = AU + E is considered, where U is a function on a domain of Rd. Here A is a smoothing linear operator and E is Gaussian white noise. The data is a realization mk of the random variable Mk = PkA U+Pk E, where Pk is a linear, finite dimensional operator related to measurement device. To allow computerized inversion, the unknown is discretized as Un=TnU, where Tn is a finite dimensional projection, leading to the computational measurement model Mkn=Pk A Un + Pk E. Bayes formula gives then the posterior distribution πkn(un | mkn)∼πn(un) exp(-1/2‖mkn - PkA un‖22) in Rd, and the mean UCMkn:=∫ un πkn(un | mk) dun is considered as the reconstruction of U. We discuss a systematic way of choosing prior distributions \priorn for all n≥ n0>0 by achieving them as projections of a distribution in a infinite-dimensional limit case. Such choice of prior distributions is \em discretization-invariant in the sense that \priorn represent the same \em a priori information for all n and that the mean UCMkn converges to a limit estimate as k,n→∞. Gaussian smoothness priors and wavelet-based Besov space priors are shown to be discretization invariant. In particular, Bayesian inversion in dimension two with B111 prior is related to penalizing the ℓ1 norm of the wavelet coefficients of U.