The Effect of Seabed Backscattering Variability on the Probability of Detection and on The Performance of Seabed Classification Algorithms

Abstract

As the scattering properties of the seafloor affect not only the mean angular dependence of backscatter but also cause a wide spread of scattered amplitudes, higher moment statistics are essential for applications such as target detection and seabed classification and characterization. The angular and frequency responses of the scattered amplitude distribution are caused primarily by water-sediment interface roughness, upper sediment heterogeneity, patchiness and discrete scatterers. To quantify the impact of seabed properties on higher moment statistics, scattered amplitudes were acquired at various sites displaying a large spectrum of seabed properties. Concurrent measurements of the seabed properties were conducted using two-dimensional stereo-photogrammetry, core and grab samples, videos and seabed penetrometers. To complement this experimental work, a temporal snapshot model based on the fourth order small slope approximation for interface scattering and on the small perturbation theory for the volume has been developed. Valid at high frequency and at all grazing angles, it allows the multiplication of scattering scenarios and will help to understand and quantify the impact of complicated seabeds on detection performance and on seabed classification algorithms. To illustrate high frequency acoustic variability, this paper presents selected experimental and simulated results.