Using scene information from a security camera to reduce false security alerts

Patent metadata

Field	Value
Publication number	US-9626849-B2
Application number	US-201514738816-A
Country	US
Kind code	B2
Filing date	Jun 12, 2015
Priority date	Jun 12, 2015
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A process reduces false positive security alerts. The process is performed at a computing device having one or more processors, and memory storing one or more programs configured for execution by the one or more processors. The process computes a depth map for a scene monitored by a video camera using a plurality of IR images captured by the video camera and uses the depth map to identify a first region within the scene having historically above average false positive detected motion events. In some instances, the first region is a ceiling, a window, or a television. The process monitors a video stream provided by the video camera to identify motion events, excluding the first region, and generates a motion alert when there is detected motion in the scene outside of the first region and the detected motion satisfies threshold criteria.

First claim

What is claimed is:

1. A method of reducing false positive security alerts, comprising:
at a computing device having one or more processors, and memory storing one or more programs configured for execution by the one or more processors:
computing a single depth map for a scene monitored by a video camera using a plurality of IR images captured by the video camera;
using depth discontinuities in the single depth map to compute a depth edge map for the scene, wherein the depth discontinuities correspond to depth differences at adjacent points exceeding a predefined depth difference threshold and the depth edge map specifies lines of depth discontinuities in the depth man;
identifying a first region within the scene that is enclosed by lines of depth discontinuities in the depth edge map;
monitoring a video stream provided by the video camera to identify motion events, excluding the first region, and generating a motion alert when there is detected motion in the scene outside of the first region and the detected motion satisfies threshold criteria.

2. The method of claim 1 , wherein the video camera has a plurality of IR illuminators and each of the plurality of IR images captured by the video camera is taken when a different subset of the illuminators is emitting light.

3. The method of claim 1 , wherein the first region is identified as a ceiling.

4. The method of claim 3 , wherein identifying the first region as a ceiling comprises:
determining that the first region is a ceiling by:
fitting a plane to points in the first region;
determining that the plane fitting residual error is less than a predefined threshold; and
determining that the plane is oriented downward.

5. The method of claim 1 , wherein the first region is identified as a window.

6. The method of claim 5 , wherein identifying the first region as a window comprises:
identifying the first region as a region of low light intensity within a captured IR image of the scene;
fitting the first region with a quadrilateral; and
determining that the absolute difference between the first region and the quadrilateral is less than a threshold percentage of the area of the quadrilateral.

7. The method of claim 1 , wherein the first region is identified as a television.

8. The method of claim 1 , wherein the computing device is a server distinct from the video camera.

9. The method of claim 1 , wherein the computing device is included in the video camera.

10. A computing device, comprising:
one or more processors;
memory; and
one or more programs stored in the memory configured for execution by the one or more processors, the one or more programs comprising instructions for:
computing a single depth map for a scene monitored by a video camera using a plurality of IR images captured by the video camera;
using depth discontinuities in the single depth map to compute a depth edge map for the scene, wherein the depth discontinuities correspond to depth differences at adjacent points exceeding a predefined depth difference threshold and the depth edge map specifies lines of depth discontinuities in the depth map;
identifying a first region within the scene that is enclosed by lines of depth discontinuities in the depth edge map;
monitoring a video stream provided by the video camera to identify motion events, excluding the first region, and generating a motion alert when there is detected motion in the scene outside of the first region and the detected motion satisfies threshold criteria.

11. The computing device of claim 10 , wherein the video camera has a plurality of IR illuminators and each of the plurality of IR images captured by the video camera is taken when a different subset of the illuminators is emitting light.

12. The computing device of claim 10 , wherein the first region is identified as a ceiling.

13. The computing device of claim 12 , wherein identifying the first region as a ceiling comprises:
determining that the first region is a ceiling by:
fitting a plane to points in the first region;
determining that the plane fitting residual error is less than a predefined threshold; and
determining that the plane is oriented downward.

14. The computing device of claim 10 , wherein the first region is identified as a window, and wherein identifying the first region as a window comprises:
identifying the first region as a region of low light intensity within a captured IR image of the scene;
fitting the first region with a quadrilateral; and
determining that the absolute difference between the first region and the quadrilateral is less than a threshold percentage of the area of the quadrilateral.

15. The computing device of claim 10 , wherein first region within the scene has historically above average false positive detected motion events.

16. The computing device of claim 10 , wherein first region within the scene has historically above average false positive detected motion events.

17. A non-transitory computer readable storage medium storing one or more programs configured for execution by a computing device having one or more processors and memory, the one or more programs comprising instructions for:
computing a single depth map for a scene monitored by a video camera using a plurality of IR images captured by the video camera;
using depth discontinuities in the single depth map to compute a depth edge map for the scene, wherein the depth discontinuities correspond to depth differences at adjacent points exceeding a predefined depth difference threshold and the depth edge map specifies lines of depth discontinuities in the depth map;
identifying a first region within the scene that is enclosed by lines of depth discontinuities in the depth edge map;
monitoring a video stream provided by the video camera to identify motion events, excluding the first region, and generating a motion alert when there is detected motion in the scene outside of the first region and the detected motion satisfies threshold criteria.

18. The non-transitory computer readable storage medium of claim 17 , wherein the one or more programs further comprise instructions for:
fitting the first region with a quadrilateral; and
determining that the absolute difference between the first region and the quadrilateral is less than a threshold percentage of the area of the quadrilateral.

19. The non-transitory computer readable storage medium of claim 17 , wherein the one or more programs further comprise instructions for:
determining that the first region is a ceiling by:
fitting a plane to points in the first region;
determining that the plane fitting residual error is less than a predefined threshold; and
determining that the plane is oriented downward.

20. The non-transitory computer readable storage medium of claim 17 , wherein the video camera has a plurality of IR illuminators and each of the plurality of IR images captured by the video camera is taken when a different subset of the illuminators is emitting light.

21. The non-transitory computer readable storage medium of claim 17 , wherein satisfying the threshold criteria comprises detecting movement of an object in the scene, and the detected movement exceeds a predefined distance within a predefined period of time.

22. The non-transitory computer readable storage medium of claim 17 , wherein satisfying the threshold criteria comprises detecting movement for an object that exceeds a predefined size.

23. The non-transitory c

Assignees

• Google Inc

Inventors

• Dixon Michael
• Shin Dongeek
• Heitz Iii George Alban
• Varadharajan Srivatsan

Classifications

• G08B13/19606 Primary

  Discriminating between target movement or movement in an area of interest and other non-signicative movements, e.g. target movements induced by camera shake or movements of pets, falling leaves, rotating fan · CPC title

• G06V20/52 Primary

  Surveillance or monitoring of activities, e.g. for recognising suspicious objects (recognising microscopic objects G06V20/69) · CPC title

• G06V10/145

  Illumination specially adapted for pattern recognition, e.g. using gratings · CPC title

• G08B13/19604

  involving reference image or background adaptation with time to compensate for changing conditions, e.g. reference image update on detection of light level change · CPC title

• H04N5/144

  Movement detection (for video coding H04N19/503; analysis of motion in general G06T7/20) · CPC title