Method for determining range of vision

• US 6,362,773 B1
• Filed: 06/26/2000
• Issued: 03/26/2002
• Est. Priority Date: 06/24/1999
• Status: Expired due to Term

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Pöchmüller, Werner
• Primary Examiner(s): Sotomayor, John B.
• Application Number:
  US09/603,073
• Time in Patent Office: 638 Days
• Field of Search: 342/70, 342/71, 342/72, 342/52, 342/53, 342/54, 342/118, 342/145, 342/176, 342/178, 342/179, 342/180, 342/197
• US Class Current: 342/52
• CPC Class Codes: G01S 13/956 mounted on ship or other platform
• CPC Class Codes: G01S 17/95 for meteorological use
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

A method via which the range of vision in a vehicle'"'"'s field of view can be determined precisely, so that with the help of range-of-vision information the driver can be advised to modify his driving style. The contrast of an object detected by a radar or lidar sensor is measured by a monocular video sensor, and the range of vision is determined from the measured values supplied by the radar or lidar sensor and by the monocular video sensor. Alternatively, the distance to and contrast of at least one object can be measured by a binocular video sensor, the range of vision then being determined from the measured contrast and distance values.

Claims

1. A method for determining a range of vision in a field of view in front of a vehicle, comprising the steps of:

measuring a contrast of at least one object located in the field of view using video technology;

causing one of a radar and a lidar sensor to measure a distance to the at least one object;

causing a monocular video sensor to measure the contrast of the at least one object detected by the one of the radar and lidar sensor; and

determining the range of vision from measured values supplied by the one of the radar and the lidar sensor and by the monocular video sensor.

4. The method according to claim 1, wherein:

the measured distance to the at least one object whose measured contrast is still adequately detectable by the human eye corresponds to the range of vision.

5. The method according to claim 1, further comprising the step of:

bringing in line the video sensor with a wavelength range that is detectable by the human eye.

6. The method according to claim 1, wherein:

the contrast measurement is carried out by the video sensor,

the method further includes the step of orienting the contrast measurement to the at least one object whose distance relative to the vehicle is changing, and

the contrast measurement and the distance measurement are carried out iteratively.

7. The method according to claim 1, further comprising the step of:

calculating a mean of measured distances to different ones of the at least one object whose contrast corresponds to a minimum value still adequately detectable by the human eye, wherein;

the mean indicates the range of vision.

8. The method according to claim 1, wherein:

the range of vision corresponds to a greatest distance among distances to different ones of the at least one object whose contrast constitutes a minimum value still detectable by the human eye.

9. The method according to claim 1, wherein:

each contrast measurement is carried out a plurality of times, and

the method further comprises the step of determining a mean contrast value from the contrast measurements.

10. The method according to claim 1, wherein:

the video sensor exhibits a non-linear transducer characteristic curve corresponding to a relationship between an incoming light intensity and an electrical output signal of the video sensor, and

a gradient of the non-linear transducer characteristic curve decreases as the incoming light intensity increases.

11. The method according to claim 1, further comprising the step of:

deactivating a headway control device in the vehicle if the range of vision has been determined t o fall below a minimum value.

12. The method according to claim 1, further comprising the step of

controlling a predefined maximum desired speed as a function of a current determined range of vision.

13. The method according to claim 1, further comprising the step of:

indicating to a driver inside the vehicle a current range of vision.

14. The method according to claim 11, further comprising the step of:

sending a signal to a driver inside the vehicle indicating that the headway control device has been deactivated.

15. The method according to claim 12, wherein:

the predefined maximum desired speed is predefined by a driver inside the vehicle, and

the method further comprises the step of sending a signal to the driver inside the vehicle indicating that the predefined maximum desired speed has been reduced based on a current range of vision.

2. A method for determining a range of vision in a field of view in front of a vehicle, comprising the steps of:

measuring a contrast of at least one object located in the field of view using video technology;

causing a binocular video sensor to measure a distance to the at least one object and to measure a contrast of the at least one object; and

determining the range of vision from values corresponding to the measured contrast and the distance.

3. The method according to claim 2, wherein:

the step of measuring is performed by one of a radar and a lidar sensor.

16. The method according to claim 2, wherein:

the measured distance to the at least one object whose measured contrast is still adequately detectable by the human eye corresponds to the range of vision.

17. The method according to claim 2, wherein:

the contrast measurement is carried out by the video sensor,

the method further includes the step of orienting the contrast measurement to the at least one object whose distance relative to the vehicle is changing, and

the contrast measurement and the distance measurement are carried out iteratively.

18. The method according to claim 2, further comprising the step of:

calculating a mean of measured distances to different ones of the at least one object whose contrast corresponds to a minimum value still adequately detectable by the human eye, wherein;

the mean indicates the range of vision.

19. The method according to claim 2, wherein:

the range of vision corresponds to a greatest distance among distances to different ones of the at least one object whose contrast constitutes a minimum value still detectable by the human eye.

20. The method according to claim 2, further comprising the step of:

deactivating a headway control device in the vehicle if the range of vision has been determined to fall below a minimum value.

21. The method according to claim 2, further comprising the step of:

controlling a predefined maximum desired speed as a function of a current determined range of vision.

22. The method according to claim 2, further comprising the step of:

indicating to a driver inside the vehicle a current range of vision.

23. The method according to claim 20, further comprising the step of:

sending a signal to a driver inside the vehicle indicating that the headway control device has been deactivated.

24. The method according to claim 21, wherein:

the predefined maximum desired speed is predefined by a driver inside the vehicle, and

the method further comprises the step of sending a signal to the driver inside the vehicle indicating that the predefined maximum desired speed has been reduced based on a current range of vision.