Method and apparatus for detecting the state of humidity on a road on which a vehicle is travelling
First Claim
1. A method of detecting the state of humidity of a road for a vehicle, the vehicle including at least one driving light for illuminating the road ahead of the vehicle and an onboard optical sensor, the method comprising the steps, while the vehicle is moving along the road in a direction of travel, with said at least one driving light in use to direct a beam of light on a zone of the road in front of the vehicle of:
- forming an image of said zone on the optical sensor, said zone comprising at least one segment oriented in the direction of travel, whereby said image is a characteristic profile representing the light distribution on the road;
establishing a reference consisting of a characteristic profile representing light distribution in at least one equivalent segment of dry road; and
comparing said image with the said reference so as to determine the instant state of humidity.
1 Assignment
0 Petitions
Accused Products
Abstract
A vehicle travels along a road with its lights on because of the conditions outside the vehicle. It has an onboard optical sensor associated with the headlights and arranged to form an image of a zone of the road in front of the vehicle, so that the state of humidity of the road can be determined, and the light output modified accordingly. The zone concerned, on the road, consists of at least one segment oriented in the direction of travel, so that the image created by the optical sensor is a characteristic curve representing the light distribution on the road. This image is compared with a reference curve to determine the state of humidity. The reference curve represents light distribution when the road is dry.
14 Citations
13 Claims
-
1. A method of detecting the state of humidity of a road for a vehicle, the vehicle including at least one driving light for illuminating the road ahead of the vehicle and an onboard optical sensor, the method comprising the steps, while the vehicle is moving along the road in a direction of travel, with said at least one driving light in use to direct a beam of light on a zone of the road in front of the vehicle of:
-
forming an image of said zone on the optical sensor, said zone comprising at least one segment oriented in the direction of travel, whereby said image is a characteristic profile representing the light distribution on the road;
establishing a reference consisting of a characteristic profile representing light distribution in at least one equivalent segment of dry road; and
comparing said image with the said reference so as to determine the instant state of humidity. - View Dependent Claims (2, 3, 4, 5, 12)
-
-
6. For a vehicle having at least one driving light, an apparatus for detecting the state of humidity on a road along which the vehicle is moving in a direction of travel, with said at least one driving light directing a beam of light on the road ahead of the vehicle, said apparatus comprising an onboard optical sensor and imaging means in front of the sensor for forming on the sensor an image of a zone of the road in front of the vehicle, said zone comprising at least one segment oriented in the direction of travel, whereby said image is a characteristic profile representing the light distribution on the road;
- memory means for storing a reference consisting of a characteristic profile corresponding to light distribution in at least one equivalent segment of dry road; and
comparison means connected to the memory means and the optical sensor for comparing said image received by the sensor with said reference. - View Dependent Claims (7, 8, 9, 10, 11, 13)
- memory means for storing a reference consisting of a characteristic profile corresponding to light distribution in at least one equivalent segment of dry road; and
Specification