Dimming

· In 2001, Gentex Corporation introduced the SmartBeam – “a headlamp-dimming technology utilizes a fully custom, forward-facing CMOS (complementary metal oxide semiconductor) image sensor that acquires images of the region ahead of the vehicle. The system then processes the images, and if no other traffic is present, it automatically activates your high beams. When the system detects other vehicles' headlamps and/or taillamps, it automatically returns your headlamps to their normal, low-beam state. In short, drivers will no longer have to manually switch between high or low beams, as Gentex's SmartBeam system will automatically modulate between the two settings based on the presence or absence of other vehicles in the sensor's pathway.”
http://www.machinevisiononline.org/public/articles/archivedetails.cfm?id=518
http://www.gentex.com/wn_smartbeam.html

· Cadillac introduced the Intellibeam in 2005 – a small light-sensing chip detects light and switches from high-beam to low-beam operation gradually as approaching vehicles get closer (system gradually increases and decreases light levels) and distinguishes between the light from oncoming cars vs. other lights from the surrounding environment; it also distinguishes tail lights and will headlights will dim as another car passes and increase in intensity again once the passing car is further away

· Intellibeam also responds to the acceleration and deceleration of the vehicle and increases or decreases the light levels accordingly
http://www.canadiandriver.com/articles/jk/050406.htm
http://www.gmtcny.com/intellibeam.htm