Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 1989;8(2):194-202.
doi: 10.1109/42.24868.

A generalized EM algorithm for 3-D Bayesian reconstruction from Poisson data using Gibbs priors

T Hebert  1 , R Leahy
Affiliations

A generalized EM algorithm for 3-D Bayesian reconstruction from Poisson data using Gibbs priors

T Hebert et al. IEEE Trans Med Imaging. 1989.

Abstract

A generalized expectation-maximization (GEM) algorithm is developed for Bayesian reconstruction, based on locally correlated Markov random-field priors in the form of Gibbs functions and on the Poisson data model. For the M-step of the algorithm, a form of coordinate gradient ascent is derived. The algorithm reduces to the EM maximum-likelihood algorithm as the Markov random-field prior tends towards a uniform distribution. Three different Gibbs function priors are examined. Reconstructions of 3-D images obtained from the Poisson model of single-photon-emission computed tomography are presented.

PubMed Disclaimer