| Topographic survey is a basic work, which is very important in the engineering construction. In recent years, traditional measurement methods have been unable to meet the requirements of some industries such as high efficiency, high safety. Laser scanning technology is one of the most representative technology of surveying and mapping which has advantage of wide range scanning, widely application. With application of airborne laser radar measurement technology in topographic survey, this problems can be better solved, meanwhile this technology can be made full use of advantage.This article mainly do work on filter and interpolation of airborne laser radar data, filter feature points and noise point, extract ground point to build DEM. Based on analyzing existing filtering algorithm, this article mainly research on moving curved surface fitting filter, points out its shortage, and put forward improvement on its basis.-first use the multilevel virtual grid to organize the data, process data in the first level of grid, then select seed point in secondary level of grid; propose the judgment mechanism in seed point selection, improve seed point reliability; use quadric surface to fit local terrain, obtain ground points by fitting elevation difference and distance from point to surface as constraint conditions; set the threshold value as multiple average of seed point, improve adaptability in some extent. At last use inverse distance to a power method for data interpolation base on virtual grid.This article do the experiment of filter with three groups of data, through qualitative analysis and quantitative analysis on the filter results, show that filter algorithm has a better effect on flat area, terrain area which change in large and building area, prove the improved algorithm has a better adaptive on terrain than moving curved surface fitting filter; then do the data interpolation of filter results by dividing mesh, fill the emptiness of data; finally extract the DEM of three groups of data. |
PDF Full Text Request