Towards a closer fusion of active and passive safety: Optical flow-based detection of vehicle side collisions

In recent years, innovative passive safety concepts have been developed that have the potential to further decrease the number of victims of traffic accidents. Such complex passive safety systems (i.e. the Daimler PRE-SAFE Pulse or inflating metal structures in the vehicle doors) typically require lead times for activation/preparation that are longer than classical crash-detecting acceleration or pressure sensors can offer. These concepts require a close integration with active safety systems in order to allow an early assessment of the type, direction, and severity of an imminent collision. This contribution proposes a prototypical side collision detection system that is based on a monocular camera positioned in the side mirrors. For collision detection, the system fuses the detection results from optical flow and a warped bird's eye view in order to allow a robust system reaction in case of an imminent collision with a dynamic object.