Stabilizing the iterative solution to ultrasonic transmissiontomography

摘要

A stable iterative reconstruction algorithm is presented fornultrasonic tomography through the uses of weighting matrices, dampingnfactor, and the features of conjugate gradient method. The weightingnmatrices are chosen according to Berryman's analysis of nonlinearntomography. An implicit conjugate gradient-type iterative formula isnused to solve a weighted least-squares problem. In the iterativenprocess, a damping factor of linear increase rather than a constant isnused to filter out the influences of smaller singular values'ncomponents. The results of simulated data show that our method cannefficiently stabilize the iteration, and provide a robust solution