Brightness adjustment system

Patent metadata

Field	Value
Publication number	US-9479706-B2
Application number	US-201313766569-A
Country	US
Kind code	B2
Filing date	Feb 13, 2013
Priority date	Feb 15, 2012
Publication date	Oct 25, 2016
Grant date	Oct 25, 2016

Abstract

A brightness adjustment system of a surround view system may include at least two adjacent image sensors providing images covering different fields of view of a user's surroundings. A first image sensor and a second image sensor of the at least two image sensors may be configured to capture images using an adjustable exposure time. An exposure time control unit may be provided that may be configured to determine, for the at least two adjacent image sensors, one or more brightness parameters from image data provided by the image sensors. The exposure time control unit may be further configured to control the exposure times of the image sensors such that the brightness parameter(s) determined for the first image sensor at least approximately matches one or more corresponding brightness parameters determined for the second image sensor.

First claim

We claim:

1. A system comprising:
a first image sensor and a second image sensor configured to capture images using an adjustable exposure time, the captured images covering different fields of view;
an exposure time control unit including first instructions executable by a processor to:
determine, for the first image sensor, one or more brightness parameters from the captured images;
determine one or more corresponding brightness parameters for the second image sensor, the second image sensor being adjacent to the first image sensor; and
control exposure times of the first image sensor, such that the one or more brightness parameters at least approximately match the one or more corresponding brightness parameters determined for the second image sensor; and

an intensity modulation unit including second instructions executable by the processor to adjust brightness of the captured images using digital image processing according to the one or more corresponding brightness parameters determined for the second image sensor, such that brightness values of the captured images for corresponding regions at least approximately match, the corresponding regions being located in marginal regions of the captured images, the marginal regions being substantially similar regions of a surrounding view.

2. The system of claim 1 , where the first and the second image sensors are arranged such that respective fields of view of the first and the second image sensors overlap.

3. The system of claim 1 , where, for the first and the second image sensors, the one or more corresponding brightness parameters represent average brightness of one or more sub-images of the captured images, and wherein the intensity modulation unit is configured to adjust brightness of images that are captured after the exposure times of the first image sensor are controlled such that the one or more brightness parameters at least approximately match the one or more corresponding brightness parameters determined for the second image sensor.

4. The system of claim 1 , where the intensity modulation unit is further configured to calculate, for the first and the second image sensors, a gray scale image for locally adjusting the brightness of the captured images provided by respective image sensors, the gray scale image being calculated using interpolation and predetermined local brightness correction factors that are calculated for defined image regions located in the marginal regions of the captured images.

5. The system of claim 4 , where the intensity modulation unit is further configured to modulate the captured images by the gray scale image to generate corresponding intensity modulated captured images.

6. The system of claim 4 , where the intensity modulation unit is further configured to determine the gray scale image using bilinear interpolation between predetermined local brightness correction factors.

7. The system of claim 4 , wherein the predetermined local brightness correction factors are calculated such that, after correction, local brightness values calculated for corresponding regions of images captured by two adjacent image sensors at least approximately match.

8. The system of claim 1 , further comprising a visualization unit configured to stitch the captured images together to generate a surround view image without performing a brightness adjustment.

9. A method comprising:
determining with a processor, for a first image sensor of at least two image sensors, one or more brightness parameters from a first captured image provided by the first image sensor;
determining, with the processor, for a second image sensor of the at least two image sensors, one or more corresponding brightness parameters from a second captured image provided by the first image sensor, the second captured image being adjacent to the first captured image;
controlling exposure times of the first image sensor with the processor so that the one or more brightness parameters at least approximately match the determined one or more corresponding brightness parameters of the second captured image provided by the second image sensor of the at least two image sensors; and
adjusting brightness of the first and the second captured images with the processor using digital image processing according to the determined one or more corresponding brightness parameters of the second image sensor such that brightness values calculated for substantially corresponding regions of the first and the second captured images at least approximately match, where the corresponding regions are located in marginal regions that represent substantially similar regions of a surrounding view.

10. The method of claim 9 , where the first and the second captured images at least partially overlap.

11. The method of claim 9 , where the determining of the one or more brightness parameters includes calculating average brightness of one or more sub-images of the first captured image.

12. The method of claim 9 , further comprising:
determining, with the processor, brightness correction factors for defined image regions located in the marginal regions;
calculating a gray scale image for adjusting the brightness of the first and the second captured images using interpolation and the determined brightness correction factors; and
modulating the first and the second captured images based on the gray scale image, the brightness correction factors calculated such that, after modulation, brightness values for corresponding regions of captured images provided by two adjacent image sensors at least approximately match.

13. The method of claim 9 , further comprising stitching the first and the second captured images together with the processor to generate one surround view image.

14. The method of claim 9 , further comprising:
calculating, with the processor, a brightness parameter for a region of the first captured image;
calculating a brightness parameter for a substantially corresponding region of the second captured image with the processor; and
calculating a brightness correction factor for the two corresponding regions with the processor such that corresponding products of a brightness correction factor and each of the brightness parameters for the two corresponding regions are approximately equal.

15. A method comprising:
sensing a first image and a second image at a first image sensor and a second image sensor, respectively to generate a first captured image and a second captured image sensed from the first image sensor and the second image sensor, respectively, the first image sensor being adjacent to the second image sensor;
determining, via a processor communicatively coupled to the first image sensor and the second image sensor, one or more respective brightness parameters of each of the first captured image and the second captured image;
determining exposure times for the first image sensor and the second image sensor with the processor based on the determined one or more respective brightness parameters for the first captured image and the second captured image, such that the one or more respective brightness parameters at least approximately match; and
adjusting the one or more respective brightness parameters using digital image processing, such that corresponding brightness values of the first captured image and the second captured image match.

16. The method of claim 15 , where the first captured image and the second captured image cover different fields of view.

17. The method of claim 15 , where the first captured image and the second captured image at least p

Assignees

• Harman Becker Automotive Systems Gmbh

Inventors

• Quast Johannes
• Scholl Kay-Ulrich
• Gassmann Bernd

Classifications

• H04N23/66 Primary

  Remote control of cameras or camera parts, e.g. by remote control devices · CPC title

• H04N23/73 Primary

  by influencing the exposure time · CPC title

• H04N23/90

  Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums · CPC title

• H04N23/698

  for achieving an enlarged field of view, e.g. panoramic image capture · CPC title

• H04N5/23238

  Electricity · mapped topic