title: Estimating the granularity coefficient of a Potts-Markov random field within a Markov chain Monte Carlo algorithm.
abstract: This paper addresses the problem of estimating the Potts parameter β jointly with the unknown parameters of a Bayesian model within a Markov chain Monte Carlo (MCMC) algorithm. Standard MCMC methods cannot be applied to this problem because performing inference on β requires computing the intractable normalizing constant of the Potts model. In the proposed MCMC method, the estimation of β is conducted using a likelihood-free Metropolis-Hastings algorithm. Experimental results obtained for synthetic data show that estimating β jointly with the other unknown parameters leads to estimation results that are as good as those obtained with the actual value of β. On the other hand, choosing an incorrect value of β can degrade estimation performance significantly. To illustrate the interest of this method, the proposed algorithm is successfully applied to real bidimensional SAR and tridimensional ultrasound images.
authors.affiliation: School of Mathematics, University of Bristol, University Walk BS8 1TW, UK. marcelopereyra@ieee.org
authors.forename: Marcelo
authors.initials: M
authors.lastname: Pereyra
authors.forename: Nicolas
authors.initials: N
authors.lastname: Dobigeon
authors.forename: Hadj
authors.initials: H
authors.lastname: Batatia
authors.forename: Jean-Yves
authors.initials: JY
authors.lastname: Tourneret