System and method for estimating size and location of moving objects

• US 9,733,127 B2
• Filed: 01/19/2016
• Issued: 08/15/2017
• Est. Priority Date: 01/19/2016
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Purohit, Aveek Ravishekhar, Saperstein, William Alan
• Primary Examiner(s): Gaworecki, Mark R
• Application Number:
  US15/000,067
• Publication Number:
  US 20170205288A1
• Time in Patent Office: 574 Days
• 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 13/19 using infrared-radiation detection systems G08B13/194 takes precedence
• CPC Class Codes: G08B 13/2494 by interference with electro-magnetic field distribution combined with other electrical sensor means, e.g. microwave detectors combined with other sensor means
• CPC Class Codes: G08B 29/18 Prevention or correction of operating errors G08B29/02, G08B29/12 take precedence

Abstract

A system is disclosed for determining the size and location of an object in a monitored area. The system includes a passive infrared sensor (PIR) configured to detect infrared radiation in a monitored area, a lens system including a plurality of lenslets, the plurality of lenslets encoded to create a mask area within the monitored area, a reflective element configured to focus the infrared radiation in the monitored area onto the PIR sensor, and a processor. The processor is configured to detect a moving object in the monitored area, initiate the movement of the reflective element, generating an object signature over time as the reflective element is moved, and the size and location of the object is determined based on the object signature.

Claims

1. A system comprising:

a passive infrared (PIR) sensor configured to detect infrared radiation in a monitored area;

a lens system including a plurality of lenslets, the plurality of lenslets encoded to create a mask area within a field of view of the monitored area;

a reflective element configured to focus the detected infrared radiation in the monitored area onto the PIR sensor; and

a processor configured to;

detect a moving object in the monitored area;

initiate movement of the reflective element;

generating an object signature over time based on the detected IR focused onto the PIR sensor as the reflective element moves; and

determining a size and location of the object based on the object signature.

2. The system of claim 1, wherein the processor is further configured to:

retrieve from a pattern database one or more pattern signatures; and

compare the retrieved one or more pattern signatures to the object signature,

wherein the pattern signature that is determined to be most similar to the object signature is used to determine the size and location of the moving object.

3. The system of claim 2, wherein the processor is further configured to initiate an alarm signal when the object signature is above a threshold signal.

4. The system of claim 2, wherein the processor is further configured to turn on a light in the monitored area when the object signature is above a threshold signal.

5. The system of claim 2, wherein the mask area is moved through a field of view of the monitored area as the reflective element is moved.

6. The detection system of claim 1, wherein the processor is configured to compare the object signature to a threshold signature.

7. The system of claim 6, wherein the processor is further configured to:

initiate an alarm signal when the object signature is greater than the threshold signature; and

turning on one or more lights in the monitored area when the object signature is greater than the threshold signature.

8. A method comprising:

detecting infrared radiation in a monitored area by a passive infrared (PIR) sensor;

initiating a movement of a reflective element when a moving object is detected in the monitored area by a processor;

generating an object signature of the detected IR of the moving object over time as the reflective element moves; and

determining a size and location of the object based on the generated object signature.

9. The method of claim 8, further comprising:

retrieving from a pattern database one or more pattern signatures; and

comparing the retrieved one or more pattern signatures to the object signature,

wherein the pattern signature that is determined to be most similar to the object signature is used to determine the size and location of the detected object.

10. The method of claim 9, further comprising initiating an alarm signal when the object signature is above a threshold signal.

11. The method of claim 9, further comprising turning on a light in the monitored area when the object signature is above a threshold signal.

12. The method of claim 8,

wherein the movement of the reflective element moves a mask area through the monitored area, and

wherein the mask area prevents the PIR sensor from sensing infrared radiation in the mask area.

13. The method of claim 8, further comprising comparing, by the processor, the object signature to a threshold signature.

14. The method of claim 13, further comprising initiating an alarm signal when the object signature is greater than the threshold signature.

15. The method of claim 13, further comprising turning on one or more lights in the monitored area when the object signature is greater than the threshold signature.

16. The method of claim 8, wherein the reflective element is configured to focus the infrared radiation in the monitored area on the PIR sensor.

17. The method of claim 16, wherein the reflective element is a mirror.