Research On The Technique Of Camera Calibration And Measurement Of Traffic Accident Scene

Current our country is in a high rate of the traffic accidents. The road accidents have gravely affected the development of the national economy and the stability of society as well as the construction of the harmonious society. Because the traffic accidents happen in a moment and a lot of details are unable to find out and the traffic accidents also extremely easy to bring about illusion, we cannot based on subjective and groundless conclusion.At present, the process of handling traffic accidents is mainly divided into three stages:The first is inspecting and obtaining evidence of the accident on-site, the second is analyzing the causes and process of the accidents, the third is duty-affirming of traffic accident according to the result of analysis. In above three stages, the work of the first stage is to be completed in the scene of a traffic accident. The duration time of the first-stage decides the degree of the traffic affected directly. The photographs of the scene of a traffic accident and the vehicles have detailed and entire information about these. So it is important to improve the accuracy of the accident reproduction that we study the photographs applied in accident scene to measure the data of the accident scene.Based on analysis of the properties of traffic accident scene, a new method of camera calibration with X-corners patterns was proposed .That is to say that it can take several scene photos with X-corners patterns from different views. On the basis of the Tsai method, camera was calibrated according to linear model and then its nonlinear parameters were modified based on the maximum likelihood criterion. At last the image was emendated according to new parameters and then the final parameters of the model were achieved. The experiment results demonstrate that the proposed method is not only simple and accurate, but also flexible.This paper mainly studies the extraction method of calibration of characteristic points, camera models and calibration methods etc. The details are followed: 1,According to the unique character of the X-corners, this paper has brought forward one kind of new improved X-corners approach algorithm based on the SV algorithm. And it has carried out comparison on various corner detection algorithms.During the process of camera calibration, recognizing and locating the internal corners of a planar checkerboard pattern image is very important. In order to do online calibration for blurred image, we propose an improved algorithm of SV for X-corner detection based on the special character of X-corners. Experimental results show that the proposed algorithm can achieve excellent effects in X-corners detecting .And it can apply to the camera calibration on line.2,This paper describes the calibration methods of traditional camera and improves the Tsai methods. It also proposes the full steps and procedure of camera calibration.Camera calibration is the key of vision measuring. The calibration accuracy and calculation speed are important indicators of calibration algorithm. The improved Tsai method has considered lens radial direction distortion, and has decreased by arithmetic amounts at the same time.3,Under the premise of the simplification of the scene process, the request of Photography and the placement of model, this paper enhances the accuracy of scene measurement, especially the accuracy of scene measurement in great range.4,This paper applies photogrammetry technology to handle traffic accidents. It implements the traffic accident measurement module and introduces the measurement system of the traffic accident scene in details..Measurement algorithm has fine measurement accuracy, and the measurement module can provide a lot of information at the scene for the three-dimensional traffic accident simulation systems.