High-resolution inversion of ultrasonic traces

An algorithm for estimating the acoustic reflection coefficient profile from ultrasonic traces obtained during inspection of layered materials is described. Given the measured trace and the incident wavelet, the inversion proceeds by means of a layer stripping approach combined with high-resolution deconvolution. The inversion algorithm is stable to noise and is suitable for use with bandlimited data. It is particularly suitable for use with materials that exhibit a few large discontinuities in impedance and in which multiple reflections in the data are evident. The performance of the algorithm is illustrated in tests with synthetic and real data. An implementation of the algorithm on a TMS 320C30 signal processing board allowed the inversion of an entire set of 256 traces, each of 256 elements, in 15 s.