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

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.