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

• US 9,626,849 B2
• Filed: 06/12/2015
• Issued: 04/18/2017
• Est. Priority Date: 06/12/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Heitz, III, George Alban, Dixon, Michael, Shin, Dongeek, Varadharajan, Srivatsan
• Primary Examiner(s): TORRENTE, RICHARD T
• Application Number:
  US14/738,816
• Publication Number:
  US 20160364966A1
• Time in Patent Office: 676 Days
• Field of Search: 348155
• CPC Class Codes: G06V 10/145 Illumination specially adapted for pattern recognition, e.g. using gratings
• CPC Class Codes: G06V 20/52 Surveillance or monitoring of activities, e.g. for recognising suspicious objects recognising microscopic objects G06V20/69
• CPC Class Codes: G08B 13/19604 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 Class Codes: G08B 13/19606 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 Class Codes: G08B 13/19608 Tracking movement of a target, e.g. by detecting an object predefined as a target, using target direction and or velocity to predict its new position
• CPC Class Codes: G08B 13/1961 Movement detection not involving frame subtraction, e.g. motion detection on the basis of luminance changes in the image
• CPC Class Codes: H04N 5/144 Movement detection for video coding H04N19/503; analysis of motion in general G06T7/20
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

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.

Claims

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 computer readable storage medium of claim 17, wherein satisfying the threshold criteria comprises detecting simultaneous movement of two or more objects in the scene.