ACTIVE FACE SHADE DETECTION IN AUTO SUN-SHADE SYSTEM

• US 20100276962A1
• Filed: 04/29/2009
• Published: 11/04/2010
• Est. Priority Date: 04/29/2009
• Status: Abandoned Application

• Current Assignee: GM Global Technology Operations LLC (General Motors Company)
• Original Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust)
• Inventors: ZHANG, WENDE, Naik, Sanjeev M.
• Application Number:
  US12/432,573
• Publication Number:
  US 20100276962A1
• Time in Patent Office: Days
• US Class Current: 296/97.2
• CPC Class Codes: B60J 3/00 Antiglare equipment associated with windows or windscreens optical viewing arrangements for vehicles B60R1/00; Sun visors for vehicles sun visors having appliances for storing or holding personal property B60R7/05

Abstract

A method for identifying a sun-shade line on a vehicle driver'"'"'s face so as to automatically position a sun blocker at the appropriate location to block the sun. The method includes generating subsequent images of the vehicle driver using a low cost camera and providing a difference image from the subsequent camera images to eliminate stationary parts of the image. The method then filters the difference image to enhance the expected motion from the controlled sun blocker and to remove the un-expected motion, which generates a filter response image that includes an identification of the movement of the sun-shade line from image to image. The method then applies a threshold to the filter response image to remove portions of the filter response image that do not exceed a predetermined intensity, and performs a Hough transform on the thresholded filter response image to identify the sun-shade line on the object.

Claims

1. A method for determining a sun-shade line on an object, said method comprising:

providing subsequent images of the object;

providing a difference image from a subtraction of the subsequent images to remove stationary portions from one image to the next image;

filtering the difference image to remove motion of the object in a horizontal direction to generate a filter response image that includes portions of the subsequent images that move in a vertical direction from the one image to the next image;

thresholding the filter response image to remove the vertical moving portions in the filter response image that do not exceed a predetermined intensity threshold; and

performing a Hough transform on the threshold filter response image to identify a position of the sun-shade line on the object.

2. The method according to claim 1 wherein providing subsequent images of the object includes providing subsequent images of a vehicle driver.

3. The method according to claim 2 further comprising positioning a sun blocker in response to the identified position of the sun-shade line so that eyes of the vehicle driver are within a shadow caused by the sun blocker.

4. The method according to claim 3 wherein the sun blocker is an electro-chromic vehicle windshield.

5. The method according to claim 1 wherein filtering the difference image includes using a line detection filter.

6. The method according to claim 1 further comprising providing false alarm mitigation and tracking of the Hough transformed image to remove line segments in the image that are too short to be the sun-shade line.

7. The method according to claim 6 wherein performing false alarm mitigation and tracking includes using a Kalman filter.

8. The method according to claim 6 wherein performing false alarm mitigation and tracking includes using a particle filter.

9. The method according to claim 1 further comprising multiplying the filter response image by a negative one if movement of the sun-shade line is downward from the one image to the next image that causes a negative identification of the movement of a sun-shade line.

10. The method according to claim 1 wherein providing subsequent images of the object includes providing subsequent images of the object by a single camera.

11. A method for determining a sun-shade line on a vehicle driver, said method comprising:

providing subsequent images of the vehicle driver using a single camera;

providing a difference image from a subtraction of the subsequent images to remove stationary portions from one image to the next image;

filtering the difference image to remove motion of the object of the vehicle driver in a horizontal direction and enhance expected motion to generate a filter response image that includes portions of the subsequent images that move in a vertical direction from the one image to the next image;

multiplying the filter response image by a negative one if movement of the sun-shade line is downward from the one image to the next image that causes a negative identification of the movement of a sun-shade line;

thresholding the filter response image to remove the vertical moving portions in the filter response image that do not exceed a predetermined intensity threshold;

performing a Hough transform on the thresholded filter response image to identify a position of the sun-shade line on the vehicle driver; and

providing false alarm mitigation and tracking of the Hough transformed image to remove line segments in the image that are too short to be the sun-shade line.

12. The method according to claim 11 further comprising positioning a sun blocker in response to the identified position of the sun-shade line so that eyes of the vehicle driver are within a shadow caused by the sun blocker.

13. The method according to claim 12 wherein the sun blocker is an electro-chromic vehicle windshield.

14. The method according to claim 11 wherein providing false alarm mitigation and tracking includes using a Kalman filter or a particle filter.

15. The method according to claim 11 wherein filtering the difference image includes using a line detection filter.

16. A system for determining a sun-shade line on a vehicle driver, said system comprising:

means for providing subsequent camera images of the vehicle driver;

means for providing a difference image from a subtraction of the subsequent camera images to remove stationary portions from one image to the next image;

means for filtering the difference image to remove motion of the object of the vehicle driver in a horizontal direction to generate a filter response image that includes portions of the subsequent images that move in a vertical direction from the one image to the next image;

means for thresholding the filter response image to remove the vertical moving portions in the filter response image that do not exceed a predetermined intensity threshold;

means for performing a Hough transform on the thresholded filter response image to identify a position of the sun-shade line on the vehicle driver; and

means for providing false alarm mitigation and tracking of the Hough transformed image to remove line segments in the image that are too short to be the sun-shade line.

17. The system according to claim 16 further comprising means for positioning a sun blocker in response to the identified position of the sun-shade line so that eyes of the vehicle driver are within a shadow caused by the sun blocker.

18. The system according to claim 16 wherein the sun blocker is an electro-chromic vehicle windshield.

19. The system according to claim 16 further comprising means for multiplying the filter response image by a negative one if movement of the sun-shade line is downward from the one image to the next image that causes a negative identification of the movement of a sun-shade line.

20. The system according to claim 16 wherein the means for filtering the difference image uses a line detection filter.