Design And Implementation Of Target LED Real-time Tracking System For OCC

Optical Camera Communication（OCC）technology,as an important supplement to wireless communication technology,can assist Intelligent Transportation System（ITS）to relieve traffic pressure,enhance road traffic safety by enabling Vehicle-toVehicle（V2V）wireless communication.The OCC system is mainly composed of transmitter LED and receiver camera.In order to realize the communication between the transmitter LED and the receiver camera,the receiver camera needs to accurately track the position of the LED in real time.However,the existing target LED tracking technology research for OCC is mainly theoretical analysis,which lacks the actual test system verification and target mobility research.Aiming at the above problems,this paper uses the tracking turntable technology and the optimized tracking algorithm to obtain the position information of the target LED,designs an OCC-oriented target LED real-time tracking system.To improve the mobility support of the target and realize the automatic tracking of the target.The main work and contributions of this paper are as follows:（1）Design and implementation of OCC real-time tracking systemOCC real-time tracking system consists of transmitter modulation module,LED drive circuit,LED array,receiver camera,turntable tracking control module and corresponding software.The hardware design of the system includes the design of the LED array moving simulation device,the modulation module,the LED array driving circuit and the camera turntable tracking control module.The software design of OCC real-time tracking system includes architecture design,camera control,turntable control,and target tracking algorithm design.Among them,the camera control design is based on the focusing method of the lens to achieve clear image imaging;the turntable control design is based on the angle-based rotation method,which moves the target imaging center to the center of the field of view,and combines the target tracking algorithm to achieve automatic tracking of the target.（2）Analysis of target LED real-time tracking algorithm for OCC systemIn the OCC real-time tracking system,the LED real-time tracking algorithm based on the background frame difference,the camshift-based LED real-time tracking algorithm and the template matching-based LED real-time tracking algorithm are implemented,and the algorithm experiment scene test and performance analysis are carried out respectively.Considering the accuracy and real-time performance comprehensively,it is found that the LED real-time tracking algorithm based on template matching meets the real-time requirements of communication,and has higher accuracy than the LED real-time tracking algorithm based on background frame difference and camshift.Aiming at the problem of LED reflection caused by ground reflection,a LED detection method based on pixel area ratio is proposed to optimize the LED real-time tracking algorithm based on template matching.In the range of 10-80 m between the transmitter LED array and the receiver camera,the effectiveness of the optimized template matching-based LED real-time tracking algorithm is verified by experiments.The test results show that the average center pixel deviation in the horizontal and vertical directions of the target center of the OCC real-time tracking system is about 20 pixels,and the target center can be stabilized in the center of the field of view of the camera image.The OCC-oriented target LED real-time tracking system designed and implemented in this paper lays the foundation for the application of V2 V and other practical scenarios.