DETECTION OF OBSTACLES AT NIGHT BY ANALYSIS OF SHADOWS

• US 20130147957A1
• Filed: 12/11/2012
• Published: 06/13/2013
• Est. Priority Date: 12/12/2011
• Status: Active Grant

• Current Assignee: MobilEye Vision Technologies Ltd. (Intel Corporation)
• Original Assignee: Mobileye Technologies Limited (Intel Corporation)
• Inventors: Stein, Gideon
• Granted Patent: US 9,297,641 B2
• Time in Patent Office: Days
• US Class Current: 348/148
• CPC Class Codes: G01B 11/02 for measuring length, width or thickness G01B11/08 takes precedence
• CPC Class Codes: G06V 20/58 Recognition of moving objects or obstacles, e.g. vehicles or pedestrians; Recognition of traffic objects, e.g. traffic signs, traffic lights or roads

Abstract

A driver assistance systems mountable in a host vehicle while the host vehicle is moving forward with headlights on for detection of obstacles based on shadows. The driver assistance system includes a camera operatively connectible to a processor. A first image frame and a second image frame are captured of a road. A first dark image patch and a second dark image patch include intensity values less than a threshold value. The first and the second dark image patches are tracked from the first image frame to the second image frame as corresponding images of the same portion of the road. Respective thicknesses in vertical image coordinates are measured of the first and second dark image patches responsive to the tracking.

Claims

1. A computerized method performable at night by a driver assistance system mountable in a host vehicle while the host vehicle is moving forward with headlights on, wherein the driver assistance system includes a camera operatively connectible to a processor, the method comprising:

capturing a first image frame and a second image frame of a road in the field of view of the camera;

processing said first image frame and said second image frame to locate a first dark image patch of said first image frame and a second dark image patch of said second image frame;

tracking said first and said second dark image patches from said first image frame to said second image frame as corresponding images of the same portion of the road; and

measuring respective thicknesses in vertical image coordinates of said first and second dark image patches responsive to said tracking from said first image frame to said second image frame.

2. The method of claim 1, wherein said processing is performed by filtering said first image frame and said second image frame with a threshold value of gray scale to produce said first dark image patch of said first image frame and said second dark image patch of said second image frame, wherein said first dark image patch and said second dark image patch include intensity values less than said threshold value;

3. The method of claim 1, further comprising:

prior to said tracking, verifying connectivity of picture elements within said first dark image patch.

4. The method of claim 1, further comprising

determining that a change of said thicknesses between said first and second dark image patches is consistent with a shadow cast by an obstacle in the road from illumination from the headlights, thereby detecting said obstacle in the road.

5. The method of claim 4, further comprising:

audibly warning a driver of the host vehicle responsive to said detecting said obstacle.

6. The method of claim 4, further comprising:

analyzing change in said thicknesses between said first and second image frames, thereby distinguishing between the detected obstacle being a positive or a negative obstacle.

7. The method of claim 4, further comprising:

analyzing change in said thicknesses between said first and second image frames, thereby computing a shape of the detected obstacle.

8. The method of claim 1, further comprising:

determining that a change of said thicknesses between said first and second image frames is not consistent with a shadow cast by an obstacle from illumination from the headlights.

9. The method of claim 1, wherein said thicknesses are measured in picture elements according to a total number of picture elements with intensity values less than said threshold divided by a width in picture element columns of said first and second dark image patches.

10. A driver assistance system including a camera and a processor configured to perform the computerized method, according to claim 1.

11. A driver assistance system mountable in a host vehicle, the driver assistance system includes a camera operatively connectible to a processor, wherein the driver assistance system while the host vehicle is moving is operable to:

capture a first image frame and a second image frame of a road in the field of view of the camera;

process said first image frame and said second image frame to locate a first dark image patch of said first image frame and a second dark image patch of said second image frame;

track said first and second dark image patches from said first image frame to said second image portion of said second image frame as corresponding images of the same portion of the road; and

measure respective thicknesses in vertical image coordinates of said first and second dark image patches responsive to said tracking from said first image frame to said second image frame.

12. The driver assistance system of claim 11, further operable to determine that a change of said thicknesses between said first and second dark image patches is consistent with a shadow cast by an obstacle in the road from illumination from the headlights, thereby detecting said obstacle in the road.

13. The driver assistance system of claim 12, further operable to analyze change in said thicknesses between said first and second image frames to distinguish between the detected obstacle being a positive or a negative obstacle.

14. The driver assistance system of claim 12, further operable to analyze change in said thicknesses between said first and second image frames to compute a shape of the detected obstacle.

15. The driver assistance system of claim 11, further operable to determine that a change of said thicknesses between said first and second image frames is not consistent with a shadow cast by an obstacle from illumination from the headlights.