Advanced PSO algorithms and local search strategies for NDT-ECT inverse problems

This paper studies the efficiency of some advanced Particle Swarm Optimization (PSO) algorithms, such as Standard PSO and Quantum-behaved PSO, to solve a nondestructive eddy current (NDT-ECT) inverse problem. The inverse problem is formulated as an optimization problem, aiming to minimize the distance between the true 2D ECT signal, produced by the real crack and the simulated signal, produced by a potential solution (crack). To increase the efficiency of the PSO based methods, enhancements based on problem specific local search strategies are also tested in order to speed up the optimization process. The inversion schemes are compared in the three-dimensional reconstruction of partially conductive cracks, which have a uniform conductivity smaller than the conductivity of the base material and a cuboid shape.