Airborne Laser Leidaquan Waveform Data Visualization

Geospatial information is the information based on the change of time and space. The traditional ways to access geospatial information, such as geodetic, topographic maps, aerial imagery and some other ways, are not able to satisfy the speed of construction and process of development in these digital cities. Also, before and after the1990s, owing to the interest for the three-dimensional world and the improvement of the knowledge of three-dimensional and the equipment, people used the technology of laser scanning, high-precision positioning, differential GPS as well as flight control and management techniques together to build an airborne laser radar system. This system is also an outstanding contribution to the GPS space positioning system after the mapping industry. The airborne laser radar technology has been developing rapidly from the time when it was created, for this technique has a lot of advantages, such as real-time acquisition, high-precision, large volumes of data and strong anti-jamming capability. These advantages overcome the problem of the large amount of data and the shortage of time that might be encountered in updating geospatial data or in the emergency disaster mitigation. Therefore, airborne laser radar technology has been widely used in city modeling, emergency disaster mitigation, flood analysis, the detection of electric transportation, forest detection and many other fields.The research of the full-waveform of the airborne laser radar, which is a brand-new technology field, begins in recent years. Compared with the traditional airborne laser radar systems, the full-waveform airborne laser radar system can provide the point cloud with a higher density by processing the waveform parameters. This new system makes great contributions to the enrichment of the point cloud and the supply of the more prominent target information. The main content of this paper includes:1) Due to the fact that not so many people make research on airborne laser radar, this paper presents the full-waveform airborne laser radar systems and the principle of how airborne laser radar works, describes the extraction methods of the waveform parameters in detail.2) In accordance with the noise characteristics of the waveform parameters, this paper sets forth two denoising preprocessing algorithms—the histogram method and the median filtering.3) The backscatter cross-section content is described, the backscatter cross-section coefficient is calculated and the backscatter cross-section of each point is gained.4) The information of range, waveform width, waveform amplitude and backscatter cross-section are used respectively to complete the visualization works of the waveform parameters. This paper also has a brief analysis of the sensitivity of different targets in different parameter maps.