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 3A
页码：67-72
出版社：Copernicus Publications
摘要：The paper outlines an approach to compare two digital surfaces of a rock face in order to extract geometric changes and deformations. The method requires the preliminary registration of each point cloud by using techniques typical of TLS. Then, point clouds are segmented in several regions, each of them referred to a plane; this task allows to interpolate all data to obtain a set of grid DEMs per epoch. Then each pair of corresponding DEMs are subtracted point-wise to obtain the .DEM of the differences along elevation. This is then processed along a three-step procedure. First possible systematic errors or low-frequency deformations are extracted by looking for a linear component. Secondly, the remaining .DEM is check against major changes, i.e. loss of material or vegetation growth. Finally, deformations of the cliff are enhanced by analyzing the mean displacement through the convolution with a square window applied to the .DEM filtered out from holes and bushes. This technique improves the original precision of each measured point, because deformation is evaluated as mean of a sample on the .DEM. The method has been tested so far on both synthetically generated and simple real data sets
