Vision-based indicator signal detection using spatiotemporal filtering

Patent metadata

Field	Value
Publication number	US-9507347-B1
Application number	US-201615056780-A
Country	US
Kind code	B1
Filing date	Feb 29, 2016
Priority date	Jun 26, 2013
Publication date	Nov 29, 2016
Grant date	Nov 29, 2016

Abstract

An autonomous vehicle is configured to detect an active turn signal indicator on another vehicle. An image-capture device of the autonomous vehicle captures an image of a field of view of the autonomous vehicle. The autonomous vehicle captures the image with a short exposure to emphasize objects having brightness above a threshold. Additionally, a bounding area for a second vehicle located within the image is determined. The autonomous vehicle identifies a group of pixels within the bounding area based on a first color of the group of pixels. The autonomous vehicle also calculates an oscillation of an intensity of the group of pixels. Based on the oscillation of the intensity, the autonomous vehicle determines a likelihood that the second vehicle has a first active turn signal. Additionally, the autonomous vehicle is controlled based at least on the likelihood that the second vehicle has a first active turn signal.

First claim

What is claimed is:

1. A method comprising:
receiving, from an image-capture device coupled to a first vehicle, a short-exposure image of a field of view of the first vehicle including a depiction of a second vehicle, wherein the image-capture device is configured to capture the short-exposure image with a short exposure to emphasize objects having a brightness above a threshold;
identifying a group of pixels in the image based on an intensity of the group of pixels;
determining an intensity of a first color of the group of pixels;
determining an intensity of a second color of the group of pixels;
determining, based on a correlation of the intensity of the first color of the group of pixels with the intensity of the second color of the group of pixels, a likelihood that the second vehicle has an active indicator signal; and
providing instructions to control, using a computing device, the first vehicle based at least on the likelihood that the second vehicle has an active indicator signal.

2. The method of claim 1 , further comprising:
determining a bounding area within a first image including the depiction of a second vehicle, wherein the bounding area is determined based on a previously stored image, and
wherein identifying the group of pixels in the image based on the intensity of the group of pixels is performed within the bounding area.

3. The method of claim 2 , wherein the bounding area defines a region of the image in which the second vehicle is located.

4. The method of claim 1 , further comprising calculating an oscillation of the intensity of the first color of the group of pixels; and
wherein determining the likelihood that the second vehicle has an active indicator signal is further based on the oscillation.

5. The method of claim 4 , wherein the oscillation is between 0.75 and 2.5 Hertz.

6. The method of claim 4 , further comprising:
determining, based on a second oscillation of the first color of a second group of pixels, a likelihood that the second vehicle has another active indicator signal; and
determining, based on both the likelihood that the second vehicle has an active indicator signal and the likelihood that the second vehicle has another active indicator signal, a likelihood that the second vehicle has active emergency lights.

7. The method of claim 1 , further comprising identifying a sun glare based on the correlation.

8. A control system comprising:
at least one processor; and
a memory having stored thereon instructions that, upon execution by the at least one processor, cause the control system to perform functions comprising:
receiving, from an image-capture device coupled to a first vehicle, a short-exposure image of a field of view of the first vehicle including a depiction of a second vehicle, wherein the image-capture device is configured to capture the short-exposure image with a short exposure to emphasize objects having a brightness above a threshold;
identifying a group of pixels in the image based on an intensity of the group of pixels;
determining an intensity of a first color of the group of pixels;
determining an intensity of a second color of the group of pixels;
determining, based on a correlation of the intensity of the first color of the group of pixels with the intensity of the second color of the group of pixels, a likelihood that the second vehicle has an active indicator signal; and
providing instructions to control, using a computing device, the first vehicle based at least on the likelihood that the second vehicle has an active indicator signal.

9. The control system of claim 8 , further comprising instructions that cause the control system to perform:
determining a bounding area within a first image including the depiction of a second vehicle, wherein the bounding area is determined based on a previously stored image, and
wherein identifying the group of pixels in the image based on the intensity of the group of pixels is performed within the bounding area.

10. The control system of claim 9 , wherein the bounding area defines a region of the image in which the second vehicle is located.

11. The control system of claim 8 , further comprising instructions that cause the control system to perform calculating an oscillation of the intensity of the first color of the group of pixels; and
wherein determining the likelihood that the second vehicle has an active indicator signal is further based on the oscillation.

12. The method of claim 11 , wherein the oscillation is between 0.75 and 2.5 Hertz.

13. The control system of claim 11 , further comprising instructions that cause the control system to perform:
determining, based on a second oscillation of the first color of a second group of pixels, a likelihood that the second vehicle has another active indicator signal; and
determining, based on both the likelihood that the second vehicle has an active indicator signal and the likelihood that the second vehicle has another active indicator signal, a likelihood that the second vehicle has active emergency lights.

14. A non-transitory computer readable medium having stored thereon instructions, that when executed by a computing device, cause the computing device to perform functions comprising:
receiving, from an image-capture device coupled to a first vehicle, a short-exposure image of a field of view of the first vehicle including a depiction of a second vehicle, wherein the image-capture device is configured to capture the short-exposure image with a short exposure to emphasize objects having a brightness above a threshold;
identifying a group of pixels in the image based on an intensity of the group of pixels;
determining an intensity of a first color of the group of pixels;
determining an intensity of a second color of the group of pixels;
determining, based on a correlation of the intensity of the first color of the group of pixels with the intensity of the second color of the group of pixels, a likelihood that the second vehicle has an active indicator signal; and
providing instructions to control, using a computing device, the first vehicle based at least on the likelihood that the second vehicle has an active indicator signal.

15. The non-transitory computer readable medium of claim 14 , further comprising instructions that cause the computing device to perform functions comprising:
determining a bounding area within a first image including the depiction of a second vehicle, wherein the bounding area is determined based on a previously stored image, and
wherein identifying the group of pixels in the image based on the intensity of the group of pixels is performed within the bounding area.

16. The non-transitory computer readable medium of claim 15 , wherein the bounding area defines a region of the image in which the second vehicle is located.

17. The non-transitory computer readable medium of claim 14 , further comprising instructions that cause the computing device to perform functions comprising calculating an oscillation of the intensity of the first color of the group of pixels; and
wherein determining the likelihood that the second vehicle has an active indicator signal is further based on the oscillation.

18. The method of claim 17 , wherein the oscillation is between 0.75 and 2.5 Hertz.

19. The non-transitory computer readable medium of claim 14 , further comprising instructions that cause the computing device to perform functions comprising:
determining, based on a second oscillation of the first color of a second group of pixels,

Assignees

• Google Inc

Inventors

• Ogale Abhijit
• Ferguson David Ian Franklin

Classifications

• G06V20/584 Primary

  of vehicle lights or traffic lights · CPC title

• G06V20/56

  exterior to a vehicle by using sensors mounted on the vehicle · CPC title

• H04N23/73

  by influencing the exposure time · CPC title

• B60R2300/80

  characterised by the intended use of the viewing arrangement · CPC title

• G05D1/0088

  characterized by the autonomous decision making process, e.g. artificial intelligence, predefined behaviours (using knowledge based models G06N5/00) · CPC title