Research On Armed Police Force Emergency System Oriented Urban Virtual Environment Reconstruction Method

The responsibility of maintaining social stability which is shouldered by Armed Police Force'(APF) is heavier,it brings up higher standered for the APF's capacity of emergency command and disposal. Since the operations of the APF,such as be on guard duty, handling unexpected incidents, preventing terrorist activities ,are concentrated in cities, the mastery of the urban environment is directly related to the effects of tasks. The traditional emergency command systems based on the 2D urban environment are increasingly unable to meet the requirements of urban combat, more and more attentions have been paid to the APF's emergency command system based on the technique of building virtual city environment . This paper studies building technology of virtual urban environment for the APF's emergency command system,which is based on Google Earth and is in view of the characteristics of real-time, lightweight transmission of data, strong maintainability and scalability of the virtual urban environment in an APF emergency command system ,and the paper has realized some modules.The main contents and research results include:(1)Present the method of rapid 3-d modeling for the important buildings. The important building is defined as the building that has a special economic or political status, or dense population .The software of Google Earth SketchUp is used to be 3-d modeling quickly for the important buildings,which gets a 3-d model with high level of\ fineness, and introduces an height estimate of building extraction based on vanishing point and an automatic texture rectification algorithm is applied to get building facades textures, which improves the efficiency of the reconstruction and the visual reality. The modeling for important buildings can help APF to acquire more detailed informations for the important buildings.(2)Present a 3-d reconstruction method for large-scale virtual urban which is combined of Google Earth and route panorama . Firstly, an automatic route panorama generation algorithm is presented to provide the street scenes textures. The route panorama has a low amount of data, and can support compression. Secondly, a expression of simplified geometry model for street scene of the both sides of the street scene has been presented. The route panorama is used to chartlet can obtain the real and compact reconstrucion of street scene.This method has advantages of high efficiency of low volume of data.(3)Implement developing a APF emergency command prototype system. The system achieve three modules of data capture module, a 3D navigation module for command vehicle and a 3D display module for battlefield situation command center .These modules meet the requirement of operational environment, such as visualization, real-time, lightweight, and verify that the method of building virtual urban environment based on Google Earth has the characteristics of simpleness, practicality, low requirement for hardware and network environment, and extensibility..