Upsampling visual servoing for a pan and tilt camera

This paper deals with visual servoing for a pan and tilt camera embarked in a drone. Video is transmitted to the ground where images are processed on a PC, and turret controls are sent back to an on board local loop in the drone. The objective is to track any fixed object on the ground without knowledge about shape or texture and to keep it centered in the image. In that aim, an algorithm that combines feature- based and global motion estimation has been proposed. The control of the system is based on a double closed loop, the outer ones including the video analysis while the inner ones aims to control the pan and tilt speed. In order to improve the time response of the visual closed loop we propose an upsampling scheme. Upsampling means that controls are sent to the pan and tilt actuator during the convergence of the image analysis algorithm and not at the end as usual. Experimentations in real conditions show the effectiveness of the proposed scheme.