Signal processing and image restoration techniques for two-dimensional eddy current nondestructive evaluation

Abstract

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Linear and Nonlinear Image Restoration Methods for Eddy Current Nondestructive Evaluation

“…On a DEC 5000 workstation, the Wiener filter took about 2 seconds, MEM took about 1.5 minutes, simulated annealing took about 30 minutes, and the genetic algorithm took about 2 minutes. Other tests also revealed that the nonlinear methods are more reliable under various flaw-coil configurations [5].…”

“…Here we briefly review the basic idea of the neural network forward model. Details on the RBF network forward model can be found in References [2,3,4].…”

“…We have also incorporated an heuristic based on the energy of the impedance-change image to guide the flaw growth in the correct direction. Details on the new state generation algorithm can be found in Reference [3].…”

“…Accept this new state if it has a lower cost than the current state. Otherwise, accept the new state with a probability given by the Metropolis function [3]. Repeat the above process until a transition occurs.…”

“…The crossover operation should randomly incorporate the genetic materials of the two parents to generate offspring without any preference for either one of the parents. We developed an algorithm for the crossover operation that is based on examining the intersection and union of the flaw regions of the two parents [3,4]. The intersection of the two flaw regions contains genetic material common to the two parents, which is likely to be an important part of the optimal solution.…”