Analysis Technique for Layered Structures using Wiener Spiking De-Convolution

Soil and snow are type of media that generally contain several layers of different physical properties normally characterized by moisture, tortuosity, porosity, density, etc. The layers are generally separated by layer boundaries and each layer has different acoustic impedance. Stratigraphy studies are useful in many areas like warning of avalanches, estimation of water content of a snowpack, determination of the water content of soil, porosity and type of soil, etc. Researchers have proposed non-invasive acoustic techniques to determine the properties of media layers. An acoustic sound source placed at a distance from the layered structure under test is used to transmit the desired acoustic signal of appropriate bandwidth and frequency range towards it as per the requirement of the stratigraphy. The basic analysis technique generally used is cross-correlation in which the layer resolution depends on the probe signal bandwidth. A new technique for stratigraphy based on Wiener spiking deconvolution (WSD) signal processing technique is presented, in this paper. In the proposed WSD based signal processing technique the layer resolution is independent of the probe signal bandwidth. It has been demonstrated using the experiments conducted in laboratory that proposed technique is capable of resolving layers with much lower probe signal bandwidth that is actually required for a conventional technique.