A NIR Based System for Night Vision Improvement 2002-21-0029
Driver assistance systems help to reduce the number of accidents. In particular, night vision improvement systems can help to come closer to the goal of collision mitigation since 40% of all fatal accidents occur at night while only 20% of traffic happens at night. (Situation in Germany).
Besides weather condition, limited vision at night is mainly caused by the light of oncoming vehicles. To overcome this problem, different developments have been made and are going on. Decades ago, an approach using polarized light has been tested but was not pursued longer due to the huge losses of light caused by the polarizers. Adaptive curve light has been introduced in the 1960's and intelligent headlight systems, adapting the beams of the headlights to specific traffic situations, are under development. A FIR based night vision improvement system is offered as an option in Cadillac cars, and has good market acceptance. The sensor detects the far Infrared radiation of objects in front of the vehicle and shows them as a Video picture projected on the windscreen with a HUD.
At Robert Bosch a NIR based system is currently under development. It uses near Infrared radiation from the modified halogen headlight. The picture is detected with a Video camera with a new nonlinear imager with a high dynamic range, being currently under development. The range of the system is in the range of 150 to 200m at good sight (no fog or heavy rain). The advantage of this combination is on the one hand a better performance compared to the FIR system because road limit lines are seen clearly at a wide range and thus a differentiation of objects within or outside the lane can be made. On the other hand the video camera being used for night vision improvement purposes can be used during day time as well, and has a high potential for other vision based safety and comfort functions like lane departure warning (day & night), traffic sign recognition (difficult in the US), ACC Stop&Go and others.
Peter M. Knoll
Convergence International Congress & Exposition On Transportation Electronics