Method and system for evaluating brightness values in sensor images of image-evaluating adaptive cruise control systems, especially with respect to day/night distinction

• US 8,823,799 B2
• Filed: 05/20/2013
• Issued: 09/02/2014
• Est. Priority Date: 08/28/2007
• Status: Active Grant

• Current Assignee: Bendix Commercial Vehicle Systems LLC (Estate of Heinz Hermann Thiele)
• Original Assignee: Bendix Commercial Vehicle Systems LLC (Estate of Heinz Hermann Thiele)
• Inventors: Kuehnle, Andreas, Boon, Cathy
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): Anderson, Matthew J
• Application Number:
  US13/897,535
• Publication Number:
  US 20130251208A1
• Time in Patent Office: 470 Days
• Field of Search: 348/148, 348/149
• US Class Current: 348/149
• CPC Class Codes: G06V 10/141 Control of illumination
• CPC Class Codes: G06V 20/56 exterior to a vehicle by using sensors mounted on the vehicle
• CPC Class Codes: G06V 20/584 of vehicle lights or traffic lights
• CPC Class Codes: G06V 20/588 Recognition of the road, e.g. of lane markings; Recognition of the vehicle driving pattern in relation to the road

Abstract

The invention proposes a method and an arrangement for evaluating sensor images of an image-evaluating environment recognition system on a carrier, in which, in order to distinguish the light conditions in the area of the image-evaluating environment recognition system with regard to day or night, at least the gain and/or the exposure time of the at least one image sensor detecting the environment is/are monitored, a profile of the gain and/or the exposure time against time with relatively high gain or relatively long exposure times characterizing night-time light conditions, and a profile of the gain and/or the exposure time with relatively low gain and/or relatively short exposure times characterizing daytime light conditions. The environment recognition system according to the invention can also be used to search the detected environment for bright objects, the headlights of another carrier being used as additional information, for example.

Claims

1. A method for setting a parameter of an image-based driving assistance system on a vehicle, the driver assistance system including a lane-keeping assistance system, the method comprising:

creating a state recognition profile including a plurality of respective previous instantaneous gains and previous instantaneous exposure times associated with one of an instantaneous daytime state and an instantaneous night-time state;

recording a current frame;

reading at least one of a current instantaneous gain and a current instantaneous exposure time associated with the frame;

identifying, based on the state recognition profile, if the at least one of the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state, the instantaneous night-time state, and a neither daytime nor night-time state;

if the at least one of the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state and the instantaneous night-time state, adding the current instantaneous gain and the current instantaneous exposure time to the state recognition profile as an additional one of the previous instantaneous gains and previous instantaneous exposure times representing the one of the instantaneous daytime state and the instantaneous night-time state of the current instantaneous gain and the current instantaneous exposure time;

if the at least one of the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state and the instantaneous night-time state, setting a parameter of the driver assistance system based on the corresponding state of the current instantaneous gain and the current instantaneous exposure time; and

if the at least one of the current instantaneous gain and the current instantaneous exposure time do not correspond to one of the instantaneous daytime state and the instantaneous night-time state, maintaining a current state of the parameter of the driver assistance system.

2. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 1, wherein the creating step includes:

repeating the recording step, the reading step, the identifying step, and the adding step until the state recognition profile includes a number of the respective previous instantaneous gains and previous instantaneous exposure times associated with one of the instantaneous daytime state and the instantaneous night-time state.

3. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 1, wherein:

repeating the recording step, the reading step, the identifying step, the adding step, the setting step, and the maintaining step in regular cycles.

4. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 1, wherein the identifying step includes:

comparing the current instantaneous gain and the current instantaneous exposure time with gains and exposure times in the state recognition profile; and

identifying whether the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state, the instantaneous night-time state, and a neither daytime nor night-time state based on the comparison.

5. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 4, further including:

accessing the gains and exposure times in the state recognition profile via a lookup table.

6. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 1, further including:

determining respective average values of the gain and the exposure time for the state recognition profile.

7. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 6, wherein the identifying step includes:

identifying the current instantaneous gain and the current instantaneous exposure time corresponding to the neither daytime nor night-time state based on the respective average values of the gain and the exposure time for the state recognition profile.

8. The method for setting a parameter of an image-based driving assistance system on a vehicle as set forth in claim 1, further including:

determining a frequency with which bright objects and indication objects are found in a detected environment; and

establishing a connection between the night-time state and a predefined frequency of the occurrence of the bright and indication objects in the environment.

9. An apparatus used within an image-evaluating environment recognition system on a vehicle having a driver assistance system, the driver assistance system including a lane-keeping assistance system having logic capable performing:

monitoring at least one of respective gains and exposure times of images detected by an image sensor distinguishing light conditions with regard to day and night;

sensing instantaneous images in regular cycles using at least one of the gain and the exposure time of the image sensor;

creating a state recognition profile by storing at least one of instantaneous gains and instantaneous exposures of respective previously identified daytime and night-time states of previous images;

determining one of a daytime state, a night-time state, and a neither daytime nor night-time state associated with the current image based on the previously stored instantaneous gains and instantaneous exposures;

if the state of the current image is determined as one of the daytime state and the nigh-time state, setting a parameter of the driver assistance system of the image-evaluating environment recognition system based on the state associated with the current image; and

if the current image is associated with the neither daytime nor night-time state, maintaining a previously set state of the driver assistance system of the image-evaluating environment recognition system.

10. The apparatus as set forth in claim 9, having logic further capable of performing:

repeating the creating step until the state recognition profile includes a number of the instantaneous gains and instantaneous exposures of the images.

11. The apparatus as set forth in claim 10, having logic further capable of performing the setting step and the maintaining step only after the state recognition profile includes the number of the instantaneous gains and instantaneous exposures of the images.

12. The apparatus as set forth in claim 10, wherein the number of the instantaneous gains and instantaneous exposures of the images corresponds to a predefined period of time.

13. The apparatus as set forth in claim 9, wherein the determining step includes:

comparing the current instantaneous gain and the current instantaneous exposure time with gains and exposure times in the state recognition profile; and

identifying whether the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state, the instantaneous night-time state, and a neither daytime nor night-time state based on the comparison.

14. The apparatus as set forth in claim 9, having logic further capable of performing:

determining respective average values of the gain and the exposure time for the state recognition profile.

15. The apparatus as set forth in claim 14, having logic further capable of performing:

identifying the current instantaneous gain and the current instantaneous exposure time corresponding to the neither daytime nor night-time state based on the respective average values of the gain and the exposure time for the state recognition profile.

16. An apparatus used within an image-evaluating environment recognition system on a vehicle having a driver assistance system, the driver assistance system including a lane-keeping assistance system, the apparatus including:

means for creating a state recognition profile including a plurality of respective previous instantaneous gains and previous instantaneous exposure times associated with one of an instantaneous daytime state and an instantaneous night-time state;

an image sensor recording a current frame;

means for reading at least one of a current instantaneous gain and a current instantaneous exposure time associated with the frame;

means for identifying, based on the state recognition profile, if the at least one of the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state, the instantaneous night-time state, and a neither daytime nor night-time state;

if the at least one of the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state and the instantaneous night-time state, the current instantaneous gain and the current instantaneous exposure time are added to the state recognition profile as an additional one of the previous instantaneous gains and previous instantaneous exposure times representing the one of the instantaneous daytime state and the instantaneous night-time state of the current instantaneous gain and the current instantaneous exposure time;

means for setting a parameter of the driver assistance system based on the corresponding state of the current instantaneous gain and the current instantaneous exposure time, if the at least one of the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state and the instantaneous night-time state; and

if the at least one of the current instantaneous gain and the current instantaneous exposure lime do not correspond to one of the instantaneous daytime state and the instantaneous night-time state, the means for setting maintains a current state of the parameter of the driver assistance system.

17. The apparatus used within an image-evaluating environment recognition system on a vehicle as set forth in claim 16, wherein the means for identifying includes:

means for comparing the current instantaneous gain and the current instantaneous exposure time with gains and exposure times in the state recognition profile; and

means for determining whether the current instantaneous gain and the current instantaneous exposure time correspond to one of the instantaneous daytime state, the instantaneous night-time state, and a neither daytime nor night-time state based on the comparison.

18. The apparatus used within an image-evaluating environment recognition system on a vehicle as set forth in claim 17, further including:

a look-up table storing the gains and exposure times of the state recognition profile.

19. The apparatus used within an image-evaluating environment recognition system on a vehicle as set forth in claim 17, further including:

means for determining respective average values of the gain and the exposure time for the state recognition profile.

20. The apparatus used within an image-evaluating environment recognition system on a vehicle as set forth in claim 19, wherein:

the means for comparing compares the current instantaneous gain and the current instantaneous exposure time to the respective average values of the gain and the exposure time.