CT image reconstruction by stochastic relaxation

Presented in the paper is a stochastic relaxation algorithm for reconstruction of CT image from projection data obtained from four different directions. The basic idea of the algorithm presented is similar to that of the algorithm applied by S. Geman and D. Geman (1984) to image restoration. An initial configuration of an image is generated randomly. Each pixel in the image is represented by a unit in a reconstruction in a network system. An energy function describes the current states of the system. The algorithm works to minimize the energy of the system. Dynamics of the system involve visiting each unit in the reconstruction layer individually and setting its state to a new one stochastically according to a probability distribution, determined as the sigmoid of the output from all the units