Iterative processing of laser scanning data by full waveform analysis

The latest developments in laser scanners allow capturing and digitizing of the full waveform of the backscattered pulse. The waveform can be analyzed for measurement features such as range, reflectance values and spreading of the pulse. These features are used to distinguish between locally planar surface elements and partly penetrable objects caused by partial occlusions. This presegmentation and the derived range values are used to automatically generate surface primitives in the form of planes. This allows refining each range value taking the surface geometry in a close neighborhood into account. To refine the modeling of the surface, partly occluded surface areas are extended by prediction of the expected range values. This prediction is further improved by considering the surface slope for the estimated received waveform. Then the point cloud associated with the surface is enhanced by additional range values that were missed in the first processing step due to weak signal response. This procedure is repeated several times until all useful range values are considered to estimate the surface. (C) 2007 International Society for Photogrammetry and Remote Sensing, Inc. (ISPRS). Published by Elsevier B.V. All rights reserved.