TY - JOUR
T1 - String-averaging expectation-maximization for maximum likelihood estimation in emission tomography
AU - Helou, Elias Salomão
AU - Censor, Yair
AU - Chen, Tai Been
AU - Chern, I. Liang
AU - De Pierro, Álvaro Rodolfo
AU - Jiang, Ming
AU - Lu, Henry Horng Shing
PY - 2014/5
Y1 - 2014/5
N2 - We study the maximum likelihood model in emission tomography and propose a new family of algorithms for its solution, called string-averaging expectation-maximization (SAEM). In the string-averaging algorithmic regime, the index set of all underlying equations is split into subsets, called 'strings', and the algorithm separately proceeds along each string, possibly in parallel. Then, the end-points of all strings are averaged to form the next iterate. SAEM algorithms with several strings present better practical merits than the classical row-action maximum-likelihood algorithm. We present numerical experiments showing the effectiveness of the algorithmic scheme, using data of image reconstruction problems. Performance is evaluated from the computational cost and reconstruction quality viewpoints. A complete convergence theory is also provided.
AB - We study the maximum likelihood model in emission tomography and propose a new family of algorithms for its solution, called string-averaging expectation-maximization (SAEM). In the string-averaging algorithmic regime, the index set of all underlying equations is split into subsets, called 'strings', and the algorithm separately proceeds along each string, possibly in parallel. Then, the end-points of all strings are averaged to form the next iterate. SAEM algorithms with several strings present better practical merits than the classical row-action maximum-likelihood algorithm. We present numerical experiments showing the effectiveness of the algorithmic scheme, using data of image reconstruction problems. Performance is evaluated from the computational cost and reconstruction quality viewpoints. A complete convergence theory is also provided.
KW - blockiterative
KW - expectation-maximization (EM) algorithm
KW - ordered subsets expectation maximization (OSEM) algorithm, relaxed EM
KW - positron emission tomography (PET)
KW - string-averaging
KW - string-averaging EM algorithm
UR - http://www.scopus.com/inward/record.url?scp=84899724242&partnerID=8YFLogxK
U2 - 10.1088/0266-5611/30/5/055003
DO - 10.1088/0266-5611/30/5/055003
M3 - Article
AN - SCOPUS:84899724242
SN - 0266-5611
VL - 30
JO - Inverse Problems
JF - Inverse Problems
IS - 5
M1 - 055003
ER -