Influences of Vegetation on Laser Altimetry – Analysis and Correction Approaches

The influences of low vegetation on airborne laser scanning are studied. High vegetation is removed by filtering, but low vegetation causes systematic errors in digital terrain models. Many researchers have reported that the measurements are too high. The investigation of influences on the laser range measurement improves the understanding of the technology in use and gives explanations for the observed errors. The possibilities of correcting the data with information on the vegetation type are studied, using ground truth data from terrestrial measurements as reference. An alternative approach using texture measures, which does not require information on the land cover type, is presented. Texture has previously been defined for digital images and its equivalent for point clouds is presented here.