EFFECTS OF THE INCIDENCE ANGLE AND SURFACE TYPE ON THE LIDAR INTENSITY VALUE

摘要

Light Detection and Ranging is an active system, that measures distance by emitting a laser beam to the ground surface and then receiving the reflected signal. The incident angle of the laser beam and the surface type, in addition to its range and atmospheric effects, affect the received signal. Recent studies have utilized the intensity information of airborne LiDAR data for classification. However, such information was not fully explored because these studies only employed single flight lines. Typical airborne LiDAR data consist of multiple flight lines with varying overlaps (40%-60%); this condition implies that a significant portion of the ground objects can be measured from two different viewing aspects (each from adjacent flight lines). The intensity measurements obtained from different viewing aspects can be utilized to exploit the bi-directional reflectance distribution function property of the ground surface for classification. We employed the Rahman-Pinty-Verstraete model to investigate the effects of incident angle and surface type on intensity data, which were obtained with an Optech ALTM Pegasus airborne laser scanner with 60% overlap.