The Electronic Camera Gimbal

Mechanical gimbals are used in UAV to direct cameras to a target area, regardless of the vehicle attitude. We present an approach to replace the mechanical camera gimbal by a wide-angle fisheye lens and a high-resolution optical camera. The proposed article describes a method that computes a conventional camera image from the distorted image of a fish-eye lens. The method was designed for real time operation and evaluated in flight tests with a rotorcraft and a fixed wing mini-UAV. The image and the vehicle attitude data are transmitted synchronously to the ground control station using a broadband data link. The electronic camera gimbal can be controlled from inside the ground control station using a joystick. In contrast to mechanical gimbal systems, the electronic variant allows monitoring multiple target areas at the same time. The achievable image quality is evaluated based on data from conducted flight tests using two different camera systems. Opportunities and limits of the method are discussed.