Video Based Traffic Information Collection And Embedded Implemention

The collection of real-time traffic data plays a critical role in intelligent transportation system.Technological innovations have given rise to different types of traffic detectors. Meanwhile,a promising approach,video-based measurement system,has developed quickly.Since it has many advantages,for instance,wider-area detection and superior flexibility,many researches have been done in this area.In this paper,in order to develop a flexible and reliable system for detecting the traffic parameters through image sequences,the intelligent image sensors is present to improve detecting efficiency.The vehicle detection is based on the roadway,which sets two virtual loops(every virtual loop contains a transverse area and a lengthways area),like the inductive loop sensor,to detect their traffic flow parameters.The key idea of the system is converting the two-dimensional image data to one-dimensional digital temporal signals by the virtual loop,which reduces computation load.Vehicle detection and volume measurement algorithms have been accomplished through a large number of experiments and plentiful analysis in the traffic scene that can be simple or complicated.And algorithms have been emulated and testified by MATLAB.Contribution in this dissertation as follow:(1) The virtual-loop set in the image has been improved,which contains a transverse area and a lengthways area.Each virtual-loop's output signals mainly derive from the pixel difference between consecutive image frames within the transverse virtual-loop area and the pixel cost of background subtraction image within the lengthways virtual-loop area.When the virtual-loop was set,some rules about position and size of the virtual-loop have been present.(2) In the previous management of image,the mathematical morphology method,the Kirsch edge detection algorithm,the Kalman algorithm selected to updated the background within the lengthways virtual-loop area and the shadow eliminating method based on structural elements were used.(3) In order to tracking the vehicle more inerrably,system uses some important parameters such as positively and negatively credible frame,positively,negatively credible segment and so on,and an effective algorithm(punishment and reward algorithm) was present.In order to measure the volume of vehicles more inerrably and easily,the output signal produced when the head of the vehicles drove into the two transverse virtual-loop area in one lane was used.(4) A prototype system was also designed on embedded arm-linux and proved the system was real timely and convenient.Experiments have proved that the method of traffic information detection based on video was simple and available,real timely,convenient,with good tolerance and applicability.