Mesh-based global motion compensation for robust mosaicking and detection of moving objects in aerial surveillance

Global Motion Compensation is one of the key technologies for aerial image processing e.g. to detect moving objects on the ground or to generate a mosaick image of the observed area. For this task, it is necessary to estimate and compensate the motion of the pixels between the recorded frames evoked by the movement of the camera. As the camera is statically attached to a flying device such as a quadro-copter (also called Micro Air Vehicle, MAV) or a helicopter, the motion of the camera directly corresponds to the plane movements. For simplification, only a planar landscape model is used nowadays to describe the global motion of the scene. However, if objects like buildings or mountains are close to the camera, i.e. the MAV is at a low altitude, this simplification is not valid. Therefore we propose a more complex model by introducing a 2D mesh-based motion compensation technique, also known as image warping, to compensate the global motion. We show the benefits if used for mosaick creation by smaller artifacts due to perspective distortions and smaller drift problems. We also improve a moving object detection system to identify moving objects more reliably. Moreover, the proposed method is also more robust in case of lens distortions.