System and method of detecting driving conditions for a motor vehicle

• US 20050180149A1
• Filed: 01/07/2005
• Published: 08/18/2005
• Est. Priority Date: 01/09/2004
• Status: Active Grant

• Current Assignee: Valeo Vision (Valeo SE)
• Original Assignee: Valeo Vision (Valeo SE)
• Inventors: Albou, Pierre, Leleve, Joel
• Granted Patent: US 7,350,945 B2
• Time in Patent Office: Days
• US Class Current: 362/459
• CPC Class Codes: B60Q 1/0023 the element being a sensor, e.g. distance sensor, camera
• CPC Class Codes: B60Q 9/008 for anti-collision purposes
• CPC Class Codes: G01S 17/003 Bistatic lidar systems; Multistatic lidar systems
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 17/48 Active triangulation systems, i.e. using the transmission and reflection of electromagnetic waves other than radio waves
• CPC Class Codes: G01S 17/931 of land vehicles

Abstract

The invention provides a system for detecting driving conditions on a road, mounted on a motor vehicle and comprising: at least one headlight having a first light source for emitting a visible light beam, and at least one light source which is capable of being modulated, in particular at high frequency, and which emits an infra red light beam towards the scene along the road in front of the vehicle, at least one video camera for taking images of that scene, at least one light sensor for receiving the infra red light beam reflected by the scene, and optical means for directing at least part of the reflected infra red beam towards the sensor.

Claims

1. A system for detecting driving conditions on a road, the system being mounted on a motor vehicle and comprising:

at least one illuminating headlight comprising a first light source for emitting a visible light beam, together with at least one second light source for emitting an infra red light beam towards a roadscape ahead, that is to say the scene along the road ahead of the said vehicle,

and at least one video camera for taking images of the roadscape ahead,

wherein the infra red light beam carries an emitted modulated signal, especially a high frequency signal, and wherein the system includes;

at least one light sensor which is adapted to receive the infra red light beam reflected by the roadscape ahead,

optical means for directing at least part of the reflected infra red beam towards the said light sensor, and

means for detecting, in the reflected infra red beam, a received modulated signal corresponding to the emitted modulated signal, and for determining the said driving conditions as a function of the passage time or phase shift and as a function of the form of the reflected infra red beam.

2. A system according to claim 1, wherein the light sensor is a rapid photodetector.

3. A system according to claim 1, wherein the optical means comprise collimating means of the objective or lens type, for forming an image of the roadscape ahead on the light sensor.

4. A system according to claim 1, wherein the optical means comprise a reflector for reflecting at least part of the reflected infra red beam towards the video camera and towards the light sensor.

5. A system according to claim 4, wherein the reflector is a semi-transparent wafer placed inside the camera.

6. A system according to claim 1, wherein the sensor is integrated in the video camera or in the illuminating headlight.

7. A system according to claim 1, wherein the second light source is a laser diode.

8. A system according to claim 1, wherein it includes two light sensors, each said sensor being integrated in a headlight of the vehicle or in a camera.

9. A system according to claim 1, wherein it includes two said second light sources, each of which is installed in a respective headlight and each of which is arranged to emit an infra red light beam, the two said infra red light beams being captured by at least one light sensor.

10. A system according to claim 1, wherein the infra red light beam is modulated, continuously or in pulse modulation.

11. A system according to claim 9, wherein the infra red beams emitted by the two said second light sources are modulated independently of each other.

12. A method of detecting driving conditions on a road, performed by a system according to claim 1, and comprising the following operations:

emission of at least one modulated infra red light beam,

sensing of at least one infra red beam reflected by something in the roadscape ahead,

analysis of the reflected infra red beam, and

determination, as a function of the passage time or phase shift and the form of the reflected infra red beam, of at least one of the following driving conditions;

whether a nebulosity is present,

the distance between any obstacle that may be present and the motor vehicle, and

the maximum range of visibility in the presence of nebulosity.

13. A method according to claim 12, wherein the operation of determination of at least one driving condition makes use of triangulation between two second light sources and a light sensor.

14. A method according to claim 12, wherein the operation of determination of at least one driving condition makes use of triangulation between a second light source and two light sensors.

15. A method according to claim 12, wherein the operation of determination of at least one driving condition makes use of triangulation between two second light sources and two light sensors.

16. A vehicle, especially an automotive vehicle, including a system for detecting driving conditions on a road according to claim 1.