Techniques for the Extraction of Water Depth Information from Landsat Digital Data

摘要

This report is part of a continuing program for the exploitation of Landsat data for updating ocean charting of the world. Particular emphasis has been placed on developing computer techniques to best calculate and extract reliable water depth measurements from NASA supplied digital data taken from Landsat sensors over the shallow seas that are hazardous to shipping. Landsat CCT (Computer Compatible Tape) data has potential use in construction of shallow seas bathymetric charts. Special attention must be paid to the radiometric and geometric properties of the NASA supplied tapes to extract the most accurate data. Various methods for destriping tape data have been tried depending on the nature of Landsat scene and local variations of striping pattern. Geometric corrections using ground control points should be used but scene correction should be performed only once as multiple value for improving S/N, editing clouds and turbidity patterns and providing information on water clarity and bottom reflectance changes. Tests of water depth predictions from Landsat as compared to ship measurements show importance of bottom reflectance values for Landsat pixels require further investigation. Keywords: Remote bathymetry; Charting.