Design and Evaluation of a Full-Wave Surface and Bottom-Detection Algorithm for LiDAR Bathymetry of Very Shallow Waters

Abstract

Airborne Laser Bathymetry (ALB) is an attractive technology for the measurement of shallow water bodies because of the high acquisition rate and high point densities that can be achieved. Of special interest is the application of ALB in non-navigable areas where the only alternatives are conventional terrestrial surveying by wading with a pole, multi-media photogrammetry, or spectrally based depth retrieval. The challenge for laser based approaches in such very shallow waters (< 2 m) is the difficulty of discriminating between echoes from the surface and the bottom. This work presents an algorithm for the detection of surface, volume, and bottom (SVB) designed to meet this challenge while requiring only a single wavelength (532 nm) sensor. The accuracy of the algorithm is cross validated against reference measurements obtained from terrestrial survey with a total station and shows negligible bias and virtually no depth dependence for the experimental dataset.