The importance of atmospheric correction for airborne hyperspectral remote sensing of shallow waters: application to depth estimation

摘要

Accurate determination of water depth is indispensable in multiple aspects ofcivil engineering (dock construction, dikes, submarines outfalls, trenchcontrol, etc.). To determine the type of atmospheric correction mostappropriate for the depth estimation, different accuracies are required.Accuracy in bathymetric information is highly dependent on the atmosphericcorrection made to the imagery. The reduction of effects such as glint andcross-track illumination in homogeneous shallow-water areas improves theresults of the depth estimations. The aim of this work is to assess the bestatmospheric correction method for the estimation of depth in shallow waters,considering that reflectance values cannot be greater than 1.5 % becauseotherwise the background would not be seen. This paper addresses the use ofhyperspectral imagery to quantitative bathymetric mapping and explores one ofthe most common problems when attempting to extract depth information inconditions of variable water types and bottom reflectances. The current workassesses the accuracy of some classical bathymetric algorithms(Polcyn–Lyzenga, Philpot, Benny–Dawson, Hamilton, principal componentanalysis) when four different atmospheric correction methods are applied andwater depth is derived. No atmospheric correction is valid for all type ofcoastal waters, but in heterogeneous shallow water the model of atmosphericcorrection 6S offers good results.