Real Time Video Tracking The Ground Object From A Subminiature Unmanned Aerial Vehicle

The study of the real time surveillance and tracking system of the object moving on the ground from low altitude is an important application research related to multi-subject. The primary purpose of study is to develop an applied surveillance and tracking system based on a small helicopter. The system, hanged under the helicopter, is used to watch and track the object moving on the ground. It can lock the tracked object steadily through eliminate the disturbance of other objects. And it also can provide the control parameter for the helicopter flying after the object. The thesis discussed some correlative key techniques about the surveillance and tracking system, such as the algorithm of image processing, hardware, software, control operation and etc. The main contents list as follows:1. Analyzed the background and significance of the research about the surveillance and tracking system, and traced some international research projects on surveillance system. According to the general frame and the applied conditions of the surveillance system, the reasonable approaches to construct the tracking system were presented.2. Chosen the best hardware architecture to construct an experiment system for surveillance and tracking. With parallel connection control loop, the system can switch smoothly between the manual surveillance and the automatic tracking. Besides, constructed an inside experiment platform, carried the surveillance and tracking system, to simulate the worst movement of the helicopter in the tracking process.3. Researched the threshold segmentation on digital image. The multi-threshold segmentation method with adaptive tolerance based on histogram is used to segment the motion region on the dynamic image. Some disturbance subsets are confined by the pixel frequency average of gray value. The tolerance of gray subset can be calculated by the hill-climbing search algorithm with confined scope. The image can be segmented into a binary image with an incomplete object, and the segmentation is validity and real time.4. Aim at the disturbance of other objects, there are two methods to remove these objects in the motion region. From the point of view of digital image processing, the connectivity of the object can be enhanced by pyramid data structure. Each region is labeled with a unique number by scan the image once. The object region can be identified based on its position in the subwindow. From the point of view of pattern recognition, the center of gravity of the tracked object can be located by dynamic cluster in the double sub-window. The method of dynamic cluster is simpler than the method of region label, but can not identify the object's boundary unless post processing.5. Aim at the incomplete segmentation of the object, there two methods, based on the mathematical morphology and the computational geometry, to make the convex hull of the object to segment the object completely, and replace the center of gravity of the object pixels by the center of gravity of the region enveloped in hull. The convex hull made by morphology is approximate, and the computational cost is too high. The computational geometry can make a precise convex hull, and its cost is low.6. Analyzed the movement characters of the pan and tilt head. The movement of the pan and tilt head is correspond with the object tracking on the image plane. Two control modes of the movement of the pan and tilt head, speed control and position control, are discussed, and the control parameters of the aircraft's flight control system can be calculated based on the pose of the pan and tilt head relate to aircraft during the tracking process.7. Considered man's subjective factor, a friendly human computer interface was designed from the point of view of man-machine engineering. All the key operations are gathered on the mouse in the tracking view so that the operator can concentrate on the tracking view and hit the object easily. The reasonable setup of operation can decrease labor intensity.The thesis presented the theoretical foundation and validated the feasibility of the surveillance and tracking system.