期刊名称：Archiwum Fotogrametrii, Kartografii i Teledetekcji
印刷版ISSN：2083-2214
出版年度：2009
卷号：20
语种：English
出版社：Main Board of Association of Polish Surveyors
摘要：Airborne Laser Scanning (ALS) provides an effective tool for gaining data about physical terrain as well as features on the earth’s surface. The main problem in the process of analysing ALS data is filtration,i.e. the elimination of all recorded points which do not belong to the particular surface being considered. Because large datasets of points are being considered, appropriately fast algorithms are needed in order to process the data in a very short timespan. The objective of the research was to develop a universal method of fast filtration of the airborne laser scanning data based on wavelet analysis. The algorithm of two-steps filtration,which has been developed for this purpose,carries out the process of filtration in the domain of wavelet frequency. In this process,high frequencies of the signal,which can be thought as the terrain profiles,correspond to objects on the surface. Low frequencies are basically responsible for the surface of the ground. In the first step of the filtration process,based on a low pass filter of discrete wavelet transform,the identification of all points which lie away from the approximation surface,is made. Then a reduction in the height of the points is carried out as well as the construction of a final approximation surface,which is unbiased by the influence of artificial structures on the ground. This completes the filtration process. The algorithm works well both on a flat area as well as in hilly and mountainous terrain. The method has been tested on real data obtained by airborne laser scanning carried out in the “Widawa River Valley” campaign in 2005. The results of filtration are satisfactory. The accuracy of the algorithm was estimated at 95 %,with a capacity to filter 1 million points in 3.4 seconds.
其他摘要：Lotniczy skaning laserowy stanowi efektywne narzędzie do pozyskiwania informacji zarówno o fizycznej powierzchni ziemi,jak i elementach pokrycia terenu. Kluczowe za?gadnienie w przetwarzaniu danych pochodzących ze skaningu laserowego stanowi filtracja,roz
