Application Method Research Of Digital Photogrammetry Technology Used In Traffic Accident Scene Forensics

Along with our country social economy development, vehicles increased rapidly, which led to an increase in traffic accidents. Usually, a traffic accident happens in an area with large traffic volume, such as freeway, road infall and etc. If the time to handle the accident is too long, it maybe induce road block and traffic out of order. As a result, the accident scene survey should be done accurately and efficiently. Traditional accident scene survey still relies mainly on the artificial measurement, which is low-efficient and low-precision and unable to carry on for two times to the accident scene.New technologies, such as Total Station, laser metering equipment and so on have make up these deficiencies. However, digital photogrammetry is more convenient and more economic compared with these techonologies. Scene information can be acquired from scene photos directly rather than from the real scene. And photogrammetry results can be applied as input and validated conditions in traffic reconstruction.In the traffic accident photogrammetry, calibration objects should be set in the scene to be as control points or reference points. At present, calibration points are recognized and located by handiwork or semi-automatic computer recongniton. The two methods relies on manual work in some extent. In certain conditions, such as selecting and marking large numbers of points on more than three photos, points selection relying on manual work is low efficiency. Aim to solve the problem, this paper studies on recognizing the calibration points of the photos automatically, by which measure time and errors have reduced a lot and traffic accident scene survey automation has improved.In addition, this paper has studied on the application method of digital photommetry in the accident scence survey. At present, Foreigner has applied photogrammetry techonology to draw the traffic accident scene map, using photos shot on the helicopter, which is unsuitable to our country situation. Our country s study focusd on the photogrammetry application methods in the traffic accidents scene survey, which DLT method using common digital camera has been studied by the most researcher. This method has no limits to the camera types, but demands setting controls in the scene and requires more time to process the related data. This paper proposes a new method used in traffic accident scene survey by improving DLT method , discusses and summarizes the related shooting methods and scene controls setting methods.Finally, based on the methods proposed before, the paper analyzed two real traffic accidents firstly and provided the necessary 2D or 3D geometric information for the traffic accident scene mapping and process simulation. And then, the paper proposed the concept of traffic accidents scene real-time mapping system , realized the basic functions of the system s software component and illustrated the software prototype by three tests.