期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2010
卷号：XXXVIII - Part 7B
页码：360-365
出版社：Copernicus Publications
摘要：Airborne laser scanning (ALS) has become a commercially available and therefore widely used technique for obtaining the geometricstructure of the earth’s surface. For many ALS applications it is beneficial or even essential to classify the 3D point cloud intodifferent categories (e.g. ground, vegetation, building). So far, most classification techniques use the geometry of the 3D point cloudor parameters which can be gained from analyzing the geometry or the number of echoes per emitted laser shot. Decomposing theecho waveform of full-waveform laser scanners provides in addition to the 3D position of each echo its amplitude and width. Thesephysical observables are influenced by many different factors (e.g. range, angle of incidence, surface characteristics, atmosphere, etc.).Therefore, these attributes can hardly be used without radiometric calibration. In this paper the theory of the radar equation will be usedto transform amplitude and echo width into radiometric calibration values, such as backscatter cross section, backscattering coefficientsor incidence angle corrected versions of those. For this aim, external reference targets with known backscatter characteristics arenecessary for the absolute radiometric calibration. In contrast to other approaches, this paper presents the usage of natural surfaces forthis calibration task. These surfaces are observed in order to determine their backscatter characteristics independently from the ALSflight mission by a RIEGL reflectometer. Based on these observations the data of the ALS flight can be calibrated. Calibration resultsof data acquired by a RIEGL LMS-Q560 sensor are presented and discussed. Next to a strip-wise analysis, the radiometric calibrationresults of different strips in the overlapping region are studied. In this way, the accuracy of the calibration is analyzed (1) based ona very large area with approximately homogeneous backscatter characteristics, namely a parade yard, and (2) relatively by analyzingthese overlapping regions
