Penalized maximum likelihood image reconstruction with min-max incorporation of noisy side information

A method for incorporating anatomical MRI boundary side information into penalized maximum likelihood (PML) emission computed tomography (ECT) image reconstructions using a set of averaged Gibbs weights was proposed by Hero and Piramuthu (see Proc. of IEEE/EURASIP Workshop on Nonlinear Signal and Image Processing, 1997). A quadratic penalty based on Gibbs weights was used to enforce smoothness constraints everywhere in the image except across the estimated boundary of the ROI. In this methodology, a limiting form of the posterior distribution of the MRI boundary parameters was used to average the Gibbs weights obtained by Titus, Hero and Fessler (see IEEE Int. Conf. on Image Processing, vol.2, Laussane, 1996). There is an improvement in performance over the method proposed by Titus et al., when the variance of boundary estimates from the MRI data becomes significant. Here, we present the empirical performance analysis of the proposed method of averaged Gibbs weights