Flaw depth estimation is crucial in eddy current tubing inspection in order to prevent leak accidents in various types of heat exchangers. Udpa proposed a novel method using neural network to classify four different types of flaws detected by eddy current tubing inspection [1, 2]. They used as the neural network input the Fourier descriptor coefficients of cumulative angular function of flaw signal pattern curve [3]. Their classification is based on the shape differences in signal patterns because the coefficients are invariant under rotation, translation, and scaling of the signal pattern.
展开▼