An improved particle filter algorithm based on cam-shift algorithm applied to outdoor visible light communication (outdoor-VLC) is presented in this paper. In the outdoor-VLC system, accurately and completely tracking...
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An improved particle filter algorithm based on cam-shift algorithm applied to outdoor visible light communication (outdoor-VLC) is presented in this paper. In the outdoor-VLC system, accurately and completely tracking and extracting the target signal source Light Emitting Diode (LED) area is the premise for realizing communication. However, few existing studies pay attention to it. In the dynamic outdoor environment, there will be a lot of different environmental interferences (such as background interference, similar object interference, etc.), which greatly increases the difficulty of tracking and extracting the target signal source LED area. Therefore, in this paper, an improved tracking algorithm is proposed to solve the problem of how to track and extract the target signal source LED area accurately, stably and in real time in the outdoor-VLC system under various environmental interferences, so as to increase the feasibility of practical application of VLC system in outdoor scenes. This improved algorithm combines the particle filter algorithm and cam-shift algorithm originally. Experimental results show that the proposed algorithm has good accuracy, robustness and real-time performance under the environment of multiple interference factors. Accordingly, the proposed algorithm can be applied to the outdoor-VLC system with various environmental interferences, and can realize the actual first step of communication in VLC system based on image sensor well, laying a foundation for feature extraction, data transmission and other subsequent steps.
This paper proposes the design and development of an on-board autonomous visual tracking system (AVTS) for unmanned aerial vehicles (UAV). A prototype of the proposed system has been implemented in MATLAB/ Simulink fo...
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This paper proposes the design and development of an on-board autonomous visual tracking system (AVTS) for unmanned aerial vehicles (UAV). A prototype of the proposed system has been implemented in MATLAB/ Simulink for simulation purposes. The proposed system contains GPS/INS sensors, a gimbaled camera, a multi-level autonomous visual tracking algorithm, a ground stationary target (GST) or ground moving target (GMT) state estimator, a camera control algorithm, a UAV guidance algorithm, and an autopilot. The on-board multi-level autonomous visual tracking algorithm acquires the video frames from the on-board camera and calculates the GMT pixel position in the video frame. The on-board GMT state estimator receives the GMT pixel position from the multi-level autonomous visual tracking algorithm and estimates the current position and velocity of the GMT with respect to the UAV. The on-board non-linear UAV guidance law computes the UAV heading velocity rates and sends them to the autopilot to steer the UAV in the desired path. The on-board camera control law computes the control command and sends it to the camera's gimbal controller to keep the GMT in the camera's field of view. The UAV guidance law and camera control law have been integrated for continuous tracking of the GMT. The on-board autopilot is used for controlling the UAV trajectory. The simulation of the proposed system was tested with a flight simulator and the UAV's reaction to the GMT was observed. The simulated results prove that the proposed system tracks a GST or GMT effectively.
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