Deconvolution of ultrasonic echoes using Bernoulli-Gaussian processes for composite materials inspection

¹ Image and signal processing laboratory, Welding and NDT Centre, route de Dely-Ibrahim, BP 64, Chéraga, 16300 Alger, Algeria
² University of Blida, Algeria

Corresponding author: Abs_benammar@yahoo.fr

Received: 5 December 2007
Accepted: 29 March 2008

Abstract

In this work, we present an approach of deconvolution ill-posed problems of superimposed signals in time. A priori information must be taken into account to solve this problem. The a priori information translates the physical properties of the ultrasonic signals. The defect impulse response is modelled as a Bernoulli-Gaussian sequence. Deconvolution becomes the detection problem of the optimal Bernoulli sequence and estimation of the associated complex amplitudes. A simulation study on defect detection was realised, and results were validated experimentally on Carbon fiber-reinforced polymer multi-layered composite materials (CFRP) with and without delamination defects taken from aircraft.