Kinematics modeling for Tele-Observation robotic camera

Modern surveillance systems commonly use pan-tilt-zoom camera to monitor the wildlife. With the expansion of monitored area, it is a fundamental problem to acquire clear images of the interested target by controlling camera. In this paper, we propose a kinematics model of a pan-tilt-zoom robotic camera to address this problem. The pan-tilt-zoom camera can be regarded as a special Tele-Observation robot with three degrees of freedom: pan, tilt and zoom. The field of view of the pan-tilt-zoom camera is taken as the end-effector of the Tele-Observation robot. A model of the Tele-Observation robot is proposed and the model parameters are estimated. The zoom model that reflects how focal length vary as a function of zoom scale is introduced. This model has higher accuracy of target's spatial location compared with existing method, especially on the aspect of depth information. The experiments demonstrate the feasibility and effectiveness of our new model. The average relative error of the field experiment is 0.49%, which can satisfy the requirement for wild surveillance.