Image sharpening of linearized inverse scattering method for concrete voids

Linearized Inverse Scattering Methods based on Kirchhoff approximation can be applicable to visualize flaw shapes with scattering waves from the flaw. Scattering waves from the flaws are measured by pseudo UT pulse-echo mode that two probes are operated simultaneously. In order to visualize the flaws inside the concrete, Parasitic Discrete Wavelet Transform (P-DWT) is applied to extract the frequency characteristic components in the scattered waves. The basis waveform of real-signal mother wavelet (RMW) is acquired by Finite Element Method (FEM) analysis. Scattered waves are filtered by P-DWT; then, they are processed with Kirchhoff Inverse Scattering Method. The imaging process includes to select the optimum Mother Wavelet with AIC and a suitable decomposition level in the wavelet analysis. It is possible to make it highly accurate to visualize the flaws by P-DWT with RMW created from FEM analysis. (author)