Dynamic rearview mirror adaptive dimming overlay through scene brightness estimation

• US 9,445,011 B2
• Filed: 08/08/2013
• Issued: 09/13/2016
• Est. Priority Date: 10/22/2012
• Status: Active Grant

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations LLC (General Motors Company)
• Inventors: Zhang, Wende, Wang, Jinsong, Lybecker, Kent S., Piasecki, Jeffrey S., Clem, James, Green, Charles A., Frakes, Ryan M., Hester, Travis S.
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): PARIKH, DAKSHESH D
• Application Number:
  US13/962,156
• Publication Number:
  US 20140111637A1
• Time in Patent Office: 1,132 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: B60R 1/00 Optical viewing arrangements; Real-time viewing arrangements for drivers or passengers using optical image capturing systems, e.g. cameras or video systems specially adapted for use in or on vehicles
• CPC Class Codes: B60R 1/088 using a cell of electrically changeable optical characteristic, e.g. liquid-crystal or electrochromic mirrors
• CPC Class Codes: B60R 1/26 to the rear of the vehicle
• CPC Class Codes: B60R 2300/105 using multiple cameras
• CPC Class Codes: H04N 23/76 by influencing the image signals

Abstract

A vehicle imaging system includes an image capture device capturing an image exterior of a vehicle. The captured image includes at least a portion of a sky scene. A processor generates a virtual image of a virtual sky scene from the portion of the sky scene captured by the image capture device. The processor determines a brightness of the virtual sky scene from the virtual image. The processor dynamically adjusts a brightness of the captured image based the determined brightness of the virtual image. A rear view mirror display device displays the adjusted captured image.

Claims

1. A vehicle imaging system comprising:

an image capture device capturing an image exterior of a vehicle, the captured image including at least a portion of a sky scene;

a processor generating a virtual image of a virtual sky scene from the portion of the sky scene captured by the image capture device, the processor determining a brightness of the virtual sky scene from the virtual image, the processor dynamically adjusting a brightness of the captured image based the determined brightness of the virtual image; and

a rear view mirror display device for displaying the adjusted captured image;

wherein an intensity histogram is generated for a region of interest within the virtual image for analyzing the illumination conditions, the region of interest being produced from a plurality of pixels, each pixel in the region of interest including an associated light intensity value, each of the light intensity values being utilized in the intensity histogram to determine the brightness of the illumination condition of the captured image;

wherein the intensity histogram is segregated into a plurality of category bins with each bin representing a range of light intensity values, each pixel being allocated to a respective bin based on the light intensity value of each pixel;

wherein a cumulative histogram is generated based on the intensity histogram, wherein the cumulative histogram is generated to identify a respective category bin that distinguishes a daytime lighting condition from a nighttime lighting condition.

2. A vehicle imaging system of claim 1 wherein dynamically adjusting the brightness of the captured image includes darkening a road of travel in the adjusted captured image to compensate for bright illumination conditions.

3. A vehicle imaging system of claim 1 wherein dynamically adjusting the brightness of the captured image includes lightening a road of travel in the adjusted captured image to compensate for darkened illumination conditions.

4. A vehicle imaging system of claim 1 wherein the region of interest is a skyline.

5. A vehicle imaging system of claim 1 wherein the image capture device includes a wide angle field of view image capture device.

6. A vehicle imaging system of claim 1 wherein an optical axis used to generate the virtual image is different than the optical axis of the real image, wherein compensation is generated to correlate a projection of a virtual incident ray and a real incident ray.

7. A vehicle imaging system of claim 1 wherein the rear view mirror display device includes a mirror display off setting, wherein the rearview mirror display device displays only objects captured by reflection properties of the rearview mirror display device.

8. A vehicle imaging system of claim 1 wherein the rear view mirror display device includes a mirror-display-on-without-image-overlay setting, wherein the rearview mirror display device displays only the adjusted captured image.

9. A vehicle imaging system of claim 1 wherein the rear view mirror display device includes a mirror-display-on- without-image-overlay setting, wherein the rearview mirror display device displays the adjusted captured image with an image overlay, wherein the image overlay replicates components of the vehicle that would be seen by a driver in the rearview mirror display device for assisting the driver in identifying relative positioning of the vehicle with respect to surrounding objects of the vehicle.

10. A vehicle imaging system of claim 9 wherein the image overlay replicates a rear window trim of the vehicle.

11. A vehicle imaging system of claim 9 wherein the image overlay replicates a headrest of the vehicle.

12. A vehicle imaging system of claim 9 wherein the image overlay replicates a c-pillar of the vehicle.

13. A vehicle imaging system of claim 1 wherein the captured image is a skyline.

14. A method for dynamically adjusting a brightness of an image on rearview display device, the method comprising the steps of:

capturing an image exterior of a vehicle by an image capture device, the captured image including at least a portion of a sky scene;

generating a virtual image of a virtual sky scene by a processor from the portion of the sky scene captured by the image capture device, the processor determining a brightness of the virtual sky scene from the virtual image, wherein determining the brightness of the virtual sky scene from the virtual image further comprises the steps of;

generating an intensity histogram for a region of interest within the virtual image for analyzing the illumination conditions, wherein the region of interest is produced from a plurality of pixels, wherein each pixel in the region of interest includes an associated light intensity value, wherein each of the light intensity values are utilized in the intensity histogram for determining the brightness of the illumination condition of the captured image;

segregating the intensity histogram into a plurality of category bins, wherein each bin represents a range of light intensity values, and wherein each pixel is allocated to a respective bin based on the light intensity value of each pixel;

generating a cumulative histogram based on the intensity histogram, wherein the cumulative histogram is generated for identifying a respective category bin that distinguishes a daytime lighting condition from a nighttime lighting condition;

dynamically adjusting a brightness of the captured image based on the determined brightness of the virtual image; and

displaying the adjusted captured image on a rear view mirror display device for displaying the adjusted captured image.

15. The method of claim 14 wherein dynamically adjusting the brightness of the captured image includes darkening a road of travel in the adjusted captured image to compensate for bright illumination conditions.

16. The method of claim 14 wherein dynamically adjusting the brightness of the captured image includes lightening a road of travel in the adjusted captured image to compensate for darkened illumination conditions.

17. The method of claim 14 wherein the region of interest is a skyline.

18. The method of claim 14 wherein an optical axis used to generate the virtual image is different than the optical axis of the real image, wherein compensation is generated to correlate a projection of a virtual incident ray and a real incident ray.

19. The method of claim 14 wherein the rear view mirror display device includes a mirror-display-off setting, wherein the rearview mirror display device displays only objects captured by reflection properties of the rearview mirror display device when the mirror-display-off setting is enabled.

20. The method of claim 14 wherein the rear view mirror display device includes a mirror-display-on-without-image-overlay setting, wherein the rearview mirror display device displays only the adjusted captured image when the mirror-display-on-without-image-overlay setting is enabled.

21. The method of claim 14 wherein the rear view mirror display device includes a mirror-display-on- without-image-overlay setting, wherein the rearview mirror display device displays the adjusted captured image with an image overlay when the mirror-display-on- without-image-overlay setting is enabled, wherein the image overlay replicates components of the vehicle that would be seen by a driver in the rearview mirror display device for assisting the driver in identifying relative positioning of the vehicle with respect to surrounding objects of the vehicle.

22. The method of claim 21 wherein the image overlay replicates a rear window trim of the vehicle.

23. The method of claim 21 wherein the image overlay replicates a headrest of the vehicle.

24. The method of claim 21 wherein the image overlay replicates a c-pillar of the vehicle.

25. The method of claim 14 wherein dynamic view synthesis is enabled based on a driving scenario of a vehicle operation, wherein the dynamic view synthesis generates a direction zoom to a region of the image for enhancing visual awareness to a driver for the respective region.

26. The method of claim 25 wherein the driving scenario for enabling the dynamic view synthesis includes determining whether the vehicle is driving in a parking lot.

27. The method of claim 25 wherein the driving scenario for enabling the dynamic view synthesis includes determining whether the vehicle is driving in on highway.

28. The method of claim 25 wherein the driving scenario for enabling the dynamic view synthesis includes actuating a turn signal.

29. The method of claim 25 wherein the driving scenario for enabling the dynamic view synthesis is based on a steering wheel angle.

30. The method of claim 25 wherein the driving scenario of a vehicle operation for enabling the dynamic view synthesis is based on a speed of the vehicle.