학술논문

A continuation method for emission tomography
Document Type
Conference
Source
IEEE Conference on Nuclear Science Symposium and Medical Imaging Nuclear Science Symposium and Medical Imaging Conference, 1992., Conference Record of the 1992 IEEE. :1204-1206 vol.2 1992
Subject
Nuclear Engineering
Power, Energy and Industry Applications
Fields, Waves and Electromagnetics
Engineered Materials, Dielectrics and Plasmas
Signal Processing and Analysis
Bioengineering
Tomography
Radiology
Bayesian methods
Annealing
Computer science
Reconstruction algorithms
Maximum likelihood estimation
Position measurement
Detectors
Biomembranes
Language
Abstract
The authors offer a framework, deterministic annealing (DA), in which two important technical problems are addressed. One of these problems is associated with the minimization of objective functions composed of both binary and continuous variables. The second concerns local minima. The DA method offers a principled and efficient means of handling the problems associated with mixed continuous and binary variable objectives. The application of the DA method results in a sequence of objective functions (defined only on the continuous variables) whose sequence of solutions approaches that of the original mixed variable objective function. The sequence is indexed by a control parameter ( beta ). At each beta , a standard descent optimization algorithm is used to find a solution that is then used as an initial condition for the next setting of beta . The energy functions at low beta are smooth approximations of the energy functions at higher beta . Consequently, it is easier to minimize the energy functions at low beta and then track the minimum through the variation of beta .ETX