Optical Sensor Concepts for Future Head-Lighting System 2007-01-0611
To enhance drivers' convenience and safety, headlamps and headlamp control systems have been remarkably improved. For example, in daytime driving condition, auto-lighting systems support drivers especially when they repeat entering and exiting tunnels in mountain areas.
On the other hand, in nighttime driving conditions, the higher luminance headlamp HID gives drivers the enhanced visibility and Adaptive Front-lighting System (AFS) offers them the increased forward visibility on curves. Nevertheless, their performances are not yet enough developed to meet the market demands. In case of entering tunnels, the lighting-up timing is sometimes later than desired. In case of HID and AFS, their potentials are sometimes unnecessarily restrained to prevent glare to oncoming vehicles even they don't exist. These problems should be solved by adding the scene sensor to those systems.
Therefore, the scene sensor is expected to have the fundamental three functions to provide more convenience and safer headlamp control. The first function is to detect and recognize tunnels before entering. The second is to analyze the forward brightness condition including reflection from road surfaces. The final function is to distinguish the existence of preceding and oncoming vehicles.
We developed the scene sensor based on the CMOS (Complementary Metal Oxide Semiconductor) imager with the wide dynamic range; from dark tunnel to bright ambient light during daytime and from dark road surface to the bright headlamps during nighttime.
This paper concentrates on the performance of the developed proto type scene sensor that has all recognition functions.