Application of 1-D signal processing techniques for airborne laser bathymetry

The application of 1-D signal processing techniques to the preprocessing of waveforms obtained in airborne laser bathymetry is investigated. These techniques include a special type of digital smoothing for noise reduction and an appropriate lowpass digital differentiation for the detection of the bottom reflection. After preprocessing, a waveform-decomposition technique is used for sea-depth estimation. A comparative study of depth estimates obtained with corresponding estimates obtained by a surveying company is carried out. It is found that, when the resolution between the surface and bottom reflections is low, the use of the proposed techniques together with waveform decomposition leads to a more accurate separation of the surface and bottom reflections and, therefore, to more accurate sea-depth estimates. Since the processing can be readily automated, the use of these techniques can lead to manpower savings and increased productivity