The Speedometer Research Of A Motor Vehicle Based On Short-rangedouble Laser

Vehicle speed detection technology is an important part of road safety research in the field of intelligent transportation, but also the indispensable basis of the traffic police enforcement process. Therefore, the development of real-time, high accuracy vehicle speed measuring device is very necessary to improve the accuracy of the traffic police enforcement credentials and credibility to curb speeding offenses, reduce speeding causes accidents caused unnecessary losses, construct harmony road safety transport safety driving environment.With the improvement of the accuracy of laser ranging technology, especially in the field of short-range measurement the accuracy detection continue to improve, and the cost continue to lower, which lead to the more widely application of the laser ranging technology in the field of transport safety. Based on the advantages of laser ranging technology, dual-beam laser gun by two time difference between the laser and the fixed shift amount is calculated by detecting the traveling speed of the vehicle motor vehicle, having a detection accuracy, short time and anti-detection speed, etc., in the speed of the vehicle detection fields has been widely used. The main topic is divided in the following areas:(1) This paper propose a method based on double laser sensor is extracted by the two the same sampling points on the contour curve distance information and the method of time series information to calculate the vehicle speed, and sent up the speed of detection model based on compensate for body height, and this method effectively reduce the traditional dual laser short-range vehicle speedometer in use process caused by ignoring a collection of body height deformation displacement measurement error. We in-depth analysis of the double angle changes the effects of the laser sensor, the parameters of double laser short-range vehicle speedometer has carried on the quantitative analysis.(2) This paper designs a double laser velocity measuring algorithm based on contour matching point, focus on the contour curve feature extraction algorithm for real-time and reliability requirements of vehicle speed, combined with the contour curve shape characteristic mutation and orderliness determination of similarity based on discrete Frechet distance algorithm is improved, the improved algorithm not only improves the discrete Frechet distance calculation speed, but also to reflect the correspondence between the two dispersion curves between points, and finally obtained for a laser scanning motor vehicle two high profile curve similar characteristics to achieve a double-contour matching algorithm based on the laser gun point.(3) This paper complete the hardware design speed module based on Atmel’s AT91SAM9G20 processor and embedded Linux system to speed software design, implementation of the laser data receiving and processing, contour matching point extraction, calculation speed and results output.