Automatic image equalization for surround-view video camera systems

• US 8,902,313 B2
• Filed: 11/02/2011
• Issued: 12/02/2014
• Est. Priority Date: 11/02/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Rottner, Gunter, Sejalon, Frederic Marcel, Bochenek, Jeffrey
• Primary Examiner(s): Vaughn, Jr., William C
• Assistant Examiner(s): Bennett, Michael
• Application Number:
  US13/287,440
• Publication Number:
  US 20130107048A1
• Time in Patent Office: 1,126 Days
• Field of Search: 348/38, 348/148, 348/E07.085, 382/274
• US Class Current: 348/148
• 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 1/27 providing all-round vision, e.g. using omnidirectional cameras
• CPC Class Codes: B60R 2300/105 using multiple cameras
• CPC Class Codes: B60R 2300/30 characterised by the type of image processing
• CPC Class Codes: H04N 23/698 for achieving an enlarged field of view, e.g. panoramic image capture
• CPC Class Codes: H04N 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/80 Camera processing pipelines; Components thereof

Abstract

A method of automatically equalizing image data generated by a surround-view camera system of a vehicle. The method includes receiving a first, second, third, and fourth data set including image data corresponding to a front, left, right, and rear field of view of the vehicle, respectively. The method also includes identifying a darkest region in the first, second, and third data sets and adjusting a brightness of the image data included in the first, second, and third data sets based on the darkest region. The method further includes adjusting a brightness of the image data included in the fourth data set based on a comparison of the brightness of the image data included in the fourth data set and the adjusted brightness of the image data included in the second and third data sets.

Claims

1. A surround-view camera system for a vehicle, the surround-view camera system comprising:

a first camera positioned on a front side of the vehicle, the first camera producing a first data set including image data corresponding to a front field of view;

a second camera positioned on a left side of the vehicle, the second camera producing a second data set including image data corresponding to a left field of view;

a third camera positioned on a right side of the vehicle, the third camera producing a third data set including image data corresponding to a right field of view;

a fourth camera positioned on a rear side of the vehicle, the fourth camera producing a fourth data set including image data corresponding to a rear field of view; and

an electronic control unit configured to

receive the first data set, the second data set, the third data set, and the fourth data set;

identify a darkest region in the first data set, the second data set, and the third data set without considering the fourth data set;

adjust a brightness of the image data included in the first data set, the second data set, and the third data set based on the darkest region without adjusting the fourth data set; and

adjust a brightness of image data included in the fourth data set based on a comparison of the brightness of the image data included in the fourth data set and the adjusted brightness of the image data included in the second data set and the third data set without considering the first data set.

2. The surround-view camera system of claim 1, wherein the electronic control unit image stitches the adjusted image data included in the first data set, the second data set, the third data set, and the fourth data to produce a panoramic image.

3. The surround-view camera system of claim 2, further comprising a human-machine interface including a viewing screen positioned adjacent an operator of the vehicle, the human-machine interface configured to receive the panoramic image and display at least a portion of the panoramic image on the viewing screen.

4. The surround-view camera system of claim 1, wherein the electronic control unit identifies the darkest region by analyzing pixel intensity in a first and second stitching area created when the image data from the first data set, the second data set, and the third data set are image stitched.

5. The surround-view camera system of claim 1, wherein the electronic control unit adjusts the brightness of the image data included in the first data set, the second data set, and the third data set based on the darkest region by identifying a pre-set image adjustment setting based on a pixel intensity of the darkest region.

6. The surround-view camera system of claim 1, wherein the electronic control unit adjusts the brightness of the image data included in the fourth data set by reducing the brightness of the image data included in the fourth data set if the image data included in the fourth data set is brighter than the adjusted image data included in the second data set and the third data set.

7. The surround-view camera system of claim 6, wherein the electronic control unit increases the adjusted brightness of the image data included in the first, second, and third data sets if the image data included in the fourth data set is brighter than the adjusted image data included in the second data set and the third data set.

8. The surround-view camera system of claim 1, wherein the electronic control unit adjusts the brightness of the image data included in the fourth data set by increasing the brightness of the image data included in the fourth data set if the image data included in the fourth data set is not brighter than the adjusted image data included in the second data set and the third data set.

9. The surround-view camera system of claim 8, wherein the electronic control unit decreases the adjusted brightness of the image data included in the first, second, and third data sets if the image data included in the fourth data set is not brighter than the adjusted image data included in the second data set and the third data set.

10. A method of automatically equalizing image data generated by a surround-view camera system of a vehicle, the method comprising:

receiving, at an electronic control unit, a first data set including image data corresponding to a front field of view of the vehicle, a second data set including image data corresponding to a left field of view of the vehicle, a third data set including image data corresponding to a right field of view of the vehicle, and a fourth data set including image data corresponding to a rear field of view of the vehicle;

identifying, at the electronic control unit, a darkest region in the first data set, the second data set, and the third data set without considering the fourth data set;

adjusting, at the electronic control unit, a brightness of the image data included in the first data set, the second data set, and the third data set based on the darkest region without adjusting the fourth data set; and

adjusting, at the electronic control unit, a brightness of the image data included in the fourth data set based on a comparison of the brightness of the image data included in the fourth data set and the adjusted brightness of the image data included in the second data set and the third data set without considering the first data set.

11. The method of claim 10, further comprising image stitching, at the electronic control unit, the adjusted image data included in the first data set, the second data set, the third data set, and the fourth data to produce a panoramic image and displaying at least a portion of the panoramic image on a viewing screen.

12. The method of claim 10, wherein adjusting, at the electronic control unit, the brightness of the image data included in the fourth data set includes reducing the brightness of the image data included in the fourth data set if the image data included in the fourth data set is brighter than the adjusted image data included in the second data set and the third data set.

13. The method of claim 12, further comprising increasing, at the electronic control unit, the adjusted brightness of the image data included in the first, second, and third data sets if the image data included in the fourth data set is brighter than the adjusted image data included in the second data set and the third data set.

14. The method of claim 10, wherein adjusting, at the electronic control unit, the brightness of the image data included in the fourth data set includes increasing the brightness of the image data included in the fourth data set if the image data included in the fourth data set is not brighter than the adjusted image data included in the second data set and the third data set.

15. The method of claim 14, further comprising reducing, at the electronic control unit, the adjusted brightness of the image data included in the first, second, and third data sets if the image data included in the fourth data set is not brighter than the adjusted image data included in the second data set and the third data set.