Using infrared images of a monitored scene to identify windows

• US 9,554,063 B2
• Filed: 06/12/2015
• Issued: 01/24/2017
• Est. Priority Date: 06/12/2015
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Shin, Dongeek, Dixon, Michael
• Primary Examiner(s): Perungavoor, Sath V
• Assistant Examiner(s): Hilaire, Clifford
• Application Number:
  US14/738,806
• Publication Number:
  US 20160366346A1
• Time in Patent Office: 592 Days
• US Class Current: 1/1
• CPC Class Codes: G06T 2207/10016 Video; Image sequence
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/10048 Infrared image
• CPC Class Codes: G06T 2207/10152 Varying illumination
• CPC Class Codes: G06T 2207/30232 Surveillance
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06T 7/254 involving subtraction of images
• CPC Class Codes: G06T 7/514 from specularities
• CPC Class Codes: G06T 7/586 from multiple light sources, e.g. photometric stereo
• 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: G06V 2201/121 using special illumination
• CPC Class Codes: G08B 13/19602 Image analysis to detect motion of the intruder, e.g. by frame subtraction
• CPC Class Codes: G08B 13/19617 Surveillance camera constructional details
• CPC Class Codes: G08B 13/19656 Network used to communicate with a camera, e.g. WAN, LAN, Internet
• CPC Class Codes: G08B 13/19658 Telephone systems used to communicate with a camera, e.g. PSTN, GSM, POTS
• CPC Class Codes: G08B 17/10 Actuation by presence of smoke or gases , e.g. automatic alarm devices for analysing flowing fluid materials by the use of optical means
• CPC Class Codes: H04N 13/20 Image signal generators
• CPC Class Codes: H04N 13/271 wherein the generated image signals comprise depth maps or disparity maps
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/45 : for generating image signals from two or more image sensors being of different type or operating in different modes, e.g. with a CMOS sensor for moving images in combination with a charge-coupled device [CCD] for still images
• CPC Class Codes: H04N 23/56 : provided with illuminating means
• CPC Class Codes: H04N 23/661 : Transmitting camera control signals through networks, e.g. control via the Internet
• CPC Class Codes: H04N 23/667 : Camera operation mode switching, e.g. between still and video, sport and normal or high- and low-resolution modes
• CPC Class Codes: H04N 23/74 : by influencing the scene brightness using illuminating means
• CPC Class Codes: H04N 23/90 : Arrangement of cameras or camera modules, e.g. multiple cameras in TV studios or sports stadiums
• CPC Class Codes: H04N 5/33 : Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A process classifies objects in a scene. The process receives a captured IR image of a scene taken by a 2-dimensional image sensor array of a camera system while one or more IR illuminators of the camera system are emitting IR light, thereby forming an IR intensity map of the scene with a respective intensity value determined for each pixel of the IR image. The process uses the IR intensity map to identify a plurality of pixels whose corresponding intensity values are within a predefined intensity range, and clusters the identified plurality of pixels into one or more regions that are substantially contiguous. The process determines that a first region of the one or more regions corresponds to a specific material based, at least in part, on the intensity values of the pixels in the first region. The process then stores information in the memory that identifies the first region.

Claims

1. A method of classifying objects in a scene, 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;

receiving a captured IR image of a scene taken by a 2-dimensional image sensor array of a camera system while one or more IR illuminators of the camera system are emitting IR light, thereby forming an IR intensity map of the scene with a respective intensity value determined for each pixel of the IR image;

using the IR intensity map to identify a plurality of pixels whose corresponding intensity values are below a threshold value corresponding to glass;

clustering the identified plurality of pixels into one or more regions that are substantially contiguous;

determining that a first region of the one or more regions corresponds to a glass surface based, at least in part, on a difference in area between the first region and a geometrical shape containing the first region being less than a threshold percentage of the geometrical shape'"'"'s area;

storing information in the memory that identifies the first region;

receiving a video stream of the scene from the camera system;

reviewing the video stream to detect movement in the scene, wherein the first region is excluded from movement detection; and

generating a motion alert when there is motion detected at the scene outside of the first region.

2. The method of claim 1, wherein each pixel of the IR image corresponds to a unique respective image sensor in the image sensor array.

3. The method of claim 1, wherein the pixels of the IR image form a partition of the image sensors in the image sensor array and wherein at least one pixel corresponds to a plurality of image sensors in the image sensor array.

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

5. The method of claim 1, wherein the computing device is included in the camera system.

6. The method of claim 1, wherein the camera system has a plurality of IR illuminators, and forming an IR intensity map of the scene comprises:

for each of a plurality of distinct subsets of IR illuminators of the camera system, receiving a respective IR sub-image of the scene while the respective subset of IR illuminators are emitting IR light and the IR illuminators not in the respective subset are not emitting IR light;

wherein determining the respective intensity value for a respective pixel comprises computing an average of intensity values at the pixel in each of the sub-images.

7. The method of claim 1, wherein clustering the identified plurality of pixels into one or more regions further comprises using an RGB image of the scene captured using the image sensor array.

8. 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;

receiving a captured IR image of a scene taken by a 2-dimensional image sensor array of a camera system while one or more IR illuminators of the camera system are emitting IR light, thereby forming an IR intensity map of the scene with a respective intensity value determined for each pixel of the IR image;

using the IR intensity map to identify a plurality of pixels whose corresponding intensity values are below a threshold value corresponding to glass;

clustering the identified plurality of pixels into one or more regions that are substantially contiguous;

determining that a first region of the one or more regions corresponds to a glass surface based, at least in part, on a difference in area between the first region and a geometrical shape containing the first region being less than a threshold percentage of the geometrical shape'"'"'s area;

storing information in the memory that identifies the first region;

receiving a video stream of the scene from the camera system;

reviewing the video stream to detect movement in the scene, wherein the first region is excluded from movement detection; and

generating a motion alert when there is motion detected at the scene outside of the first region.

9. The computing device of claim 8, wherein the computing device is a server distinct from the camera system.

10. The computing device of claim 8, wherein the camera system has a plurality of IR illuminators, and forming an IR intensity map of the scene comprises:

for each of a plurality of distinct subsets of IR illuminators of the camera system, receiving a respective IR sub-image of the scene while the respective subset of IR illuminators are emitting IR light and the IR illuminators not in the respective subset are not emitting IR light;

wherein determining the respective intensity value for a respective pixel comprises computing an average of intensity values at the pixel in each of the sub-images.

11. The computing device of claim 8, wherein clustering the identified plurality of pixels into one or more regions further comprises using a depth map that was constructed using the image sensor array.

12. The computing device of claim 8, wherein the pixels of the IR image form a partition of the image sensors in the image sensor array and wherein at least one pixel corresponds to a plurality of image sensors in the image sensor array.

13. The computing device of claim 8, wherein the computing device is a server distinct from the camera system.

14. The computing device of claim 8, wherein the computing device is included in the camera system.

15. 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:

receiving a captured IR image of a scene taken by a 2-dimensional image sensor array of a camera system while one or more IR illuminators of the camera system are emitting IR light, thereby forming an IR intensity map of the scene with a respective intensity value determined for each pixel of the IR image;

using the IR intensity map to identify a plurality of pixels whose corresponding intensity values are below a threshold value corresponding to glass;

clustering the identified plurality of pixels into one or more regions that are substantially contiguous;

determining that a first region of the one or more regions corresponds to a glass surface based, at least in part, on a difference in area between the first region and a geometrical shape containing the first region being less than a threshold percentage of the geometrical shape'"'"'s area;

storing information in the memory that identifies the first region;

receiving a video stream of the scene from the camera system;

reviewing the video stream to detect movement in the scene, wherein the first region is excluded from movement detection; and

generating a motion alert when there is motion detected at the scene outside of the first region.

16. The computer readable storage medium of claim 15, wherein the camera system has a plurality of IR illuminators, and forming an IR intensity map of the scene comprises:

for each of a plurality of distinct subsets of IR illuminators of the camera system, receiving a respective IR sub-image of the scene while the respective subset of IR illuminators are emitting IR light and the IR illuminators not in the respective subset are not emitting IR light;

wherein determining the respective intensity value for a respective pixel comprises computing an average of intensity values at the pixel in each of the sub-images.

17. The computer readable storage medium of claim 15, wherein clustering the identified plurality of pixels into one or more regions further comprises using a depth map that was constructed using the image sensor array.

18. The computer readable storage medium of claim 15, wherein clustering the identified plurality of pixels into one or more regions further comprises using an RGB image of the scene captured using the image sensor array.

19. The computer readable storage medium of claim 15, wherein each pixel of the IR image corresponds to a unique respective image sensor in the image sensor array.

20. The computer readable storage medium of claim 15, wherein the pixels of the IR image form a partition of the image sensors in the image sensor array and wherein at least one pixel corresponds to a plurality of image sensors in the image sensor array.