Laser pulse analysis for reconstruction and classification of urban objects

Current pulsed laser radar systems for topographic applications base on time-of-flight ranging techniques to determine the range of the illuminated object. The signal analysis to determine the time-of-flight typically operates with an analogous threshold detection. In this paper we describe investigations for digital recording of received laser pulses and a detailed analysis of the pulse form. Recording the complete signal is advantageous, because it allows a processing depending on different tasks, respecting intermediate results, and considering neighbourhood relations. Two different techniques for measurement of time resolved laser pulses are presented. An experimental system for a fast recording of signals was built up. For principal investigations a test board with urban materials was measured by single photon detection technique and visualized by a data cube. Based on this spatio-temporal data different features are extracted and depicted by gray value images to describe macro, meso, and micro structures. Measurements were carried out with partial occlusion of the test board by vegetation. Multiple reflections are counted by processing the data cube using a spatio-temporal filter and peak detector. First results of object segmentation are shown.
Jutzi B, Stilla U (2003) Laser pulse analysis for reconstruction and classification of urban objects. In: Ebner H, Heipke C, Mayer H, Pakzad K (eds) Photgrammetric Image Analysis PIA’03. International Archives of Photogrammetry and Remote Sensing. Vol. 34, Part 3/W8, 151-156
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