Image analysis – Applications – Vehicle or traffic control
Reexamination Certificate
2001-03-05
2003-07-01
Boudreau, Leo (Department: 2621)
Image analysis
Applications
Vehicle or traffic control
C340S930000, C340S933000
Reexamination Certificate
active
06587573
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention pertains to control systems for controlling the exterior lights of a vehicle and components that can be used with such a control system.
Modern automotive vehicles include a variety of different lamps to provide illumination under different operating conditions. Headlamps are typically controlled to alternately generate low beams and high beams. Low beams provide less illumination and are used at night to illuminate the forward path when other vehicles are present. High beams output significantly more light and are used to illuminate the vehicle's forward path when other vehicles are not present. Daytime running lights have also begun to experience widespread acceptance. In addition, super bright high beams have been proposed for use on fast rural roads. Foul weather lights, such as fog lights, are also commonly used. Other exterior vehicle lights include tail lights, brake lights center-mounted stop lights (CHMSLs), turn signals, back-up lights, cargo lights, puddle lights, license plate illuminators, etc.
Laws in various countries regulate vehicle illumination, and vehicle manufacturers must build cars that comply with these regulations. For example, regulations set forth by the United States Department of Transportation (DOT) regulate the light emissions of a vehicle's high beam headlamps. Various state regulations are used to control the amount of glare experienced by drivers due to preceding vehicles (other vehicles traveling in the same direction) and oncoming vehicles (vehicles traveling in the opposite direction).
Known vehicle high beam headlamp emissions in accordance with the DOT regulations limit the intensity to 40,000 cd at 0°, 10,000 cd at 3°, 3250 cd at 6°, 1500 cd at 9°, and 750 cd at 12. An example of an emission pattern meeting this regulation is illustrated in
FIG. 1
of U.S. Pat. No. 5,837,994, entitled CONTROL SYSTEM TO AUTOMATICALLY DIM VEHICLE HEADLAMPS, issued to Joseph Scott Stam et al. on Nov. 17, 1998, the disclosure of which is incorporated herein by reference. In order to avoid an illuminance of 0.1 foot candles (fc) incident on another vehicle at these angles, the vehicle high beam headlamps should be dimmed within 700 feet of another vehicle if the vehicles are at an angle of 0°, within 350 feet of another vehicle if the vehicles are at a horizontal position of 3°, and 200 feet of the other vehicle if the position of the other vehicle is at an angle of 6° to the longitudinal axis of the controlled vehicle. It can thus be seen that a preceding vehicle directly in front of the controlled vehicle (i.e., at an angle of 0°) will need to be identified well prior to the controlled vehicle catching up to the preceding vehicle, although the distance by which the controlled vehicle's headlamps must be dimmed for a preceding vehicle can be somewhat less than for an oncoming vehicle because glare from behind is usually less disruptive than oncoming glare.
In order to automatically control the vehicle headlamps, various headlamp dimmer control systems have been proposed. In order to prevent drivers of other vehicles from being subjected to excessive glare levels, an automatic headlamp dimmer system must sense both the headlamps of oncoming vehicles as well as the tail lights of preceding vehicles. Some systems that effectively detect headlamps are unable to adequately detect tail lights. Most prior systems are unable to distinguish nuisance light sources, such as reflectors, street signs, streetlights, house lights, or the like, from light sources that require headlight control. Accordingly, these systems are subject to undesirable dimming of the high beams when no other traffic is present and turning on the high beams when other vehicles are present. In addition to the undesirable performance, it is difficult for prior systems to comply with the legal requirements as described above for high beam control while avoiding unnecessary dimming of the vehicle headlamps.
Fog lights are examples of other vehicle lights that are difficult to control automatically. Vehicles are known to include forward and rearward directed fog lights. In Europe, it is known to provide a very bright red or white light on the back of the vehicle, which is illuminated under foggy conditions. The fog lights must be turned ON as soon as the fog reduces visibility by a predetermined amount and must turn OFF when the fog drops below that density. A reliable method of automatically controlling such fog lights has not been available.
Accordingly, there is a need for a more reliable and intelligent automatic lamp control for a vehicle.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, a control system is provided to control exterior lights of a controlled vehicle. The control system comprises an imaging system configured to image the scene forward of the controlled vehicle, and a control circuit for processing the image of the scene obtained from the imaging system and for controlling the exterior lights to change their beam pattern in response to objects detected in the processed scene, the control circuit disables automatic control of the exterior lights in response to activation of the vehicle windshield wipers.
According to another aspect of the present invention, a control system is provided to control exterior lights of a controlled vehicle. The control system comprises an imaging system configured to image the scene forward of the controlled vehicle, and a control circuit for processing the image of the scene obtained from the imaging system and for controlling the exterior lights to change their beam pattern in response to objects detected in the processed scene, the control circuit disables automatic control of the exterior lights when the vehicle windshield defroster is operating at full speed.
According to another aspect of the present invention, a control system is provided to control exterior lights of a controlled vehicle. The control system comprises an imaging system configured to image the scene forward of the controlled vehicle, and a control circuit for processing the image of the scene obtained from the imaging system and for controlling the exterior lights to change their beam pattern in response to objects detected in the processed scene, the control circuit disables automatic control of the exterior lights when snow is detected.
According to yet another embodiment, a method of detecting snowfall or fog outside a vehicle is accomplished. The method comprises the steps of: sensing light levels forward above the vehicle; comparing the relative brightness of the light levels forward and above the vehicle; and determining that it is snowing or foggy when a ratio of the relative brightness forward of the vehicle to that above the vehicle reaches a threshold.
According to another aspect of the present invention, a control system is provided to control the headlamps of a vehicle. The control system comprises an ambient light sensor for sensing the ambient light outside of the vehicle, and a control circuit for varying the beam pattern of daytime running lamps in response to the ambient light level sensed by the ambient light sensor.
According to another aspect of the present invention, a control system is provided to control the brightness of the tail lamps of a vehicle. The control system comprises an ambient light sensor for sensing the ambient light outside of the vehicle, and a control circuit for varying the brightness of the tail lamps in response to the ambient light level sensed by the ambient light sensor.
According to yet another aspect of the invention, a headlamp control system is provided for controlling the headlamps of a controlled vehicle that comprises: an imaging system configured to image the scene forward of the controlled vehicle; a control circuit coupled to the imaging system for identifying and determining the brightness of light sources in images obtained from the imaging system and for controlling the headlamps to vary a beam pattern of the headlamps as a functi
Bechtel Jon H.
Newhouse Douglas J.
Poe G. Bruce
Reese Spencer D.
Roberts John K.
Boudreau Leo
Gentex Corporation
Price Heneveld Cooper DeWitt & Litton
Tabatabai Abolfazl
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