Method and apparatus for detecting an event based on patterns of behavior

• US 20030058339A1
• Filed: 06/28/2002
• Published: 03/27/2003
• Est. Priority Date: 09/27/2001
• Status: Active Grant

• Current Assignee: Signify Holding B.V. (Signify N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Lin, Yun-Ting, Brodsky, Tomas, Trajkovic, Miroslav, Lee, Mi-Suen, Gutta, Srinivas, Philomin, Vasanth, Strubbe, Hugo, Dagtas, Serhan
• Granted Patent: US 7,369,680 B2
• Time in Patent Office: Days
• US Class Current: 348/155
• 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 7/277 involving stochastic approaches, e.g. using Kalman filters
• 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 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16
• CPC Class Codes: G08B 13/19602 Image analysis to detect motion of the intruder, e.g. by frame subtraction
• CPC Class Codes: G08B 13/19613 Recognition of a predetermined image pattern or behaviour pattern indicating theft or intrusion
• CPC Class Codes: G08B 13/19671 Addition of non-video data, i.e. metadata, to video stream
• CPC Class Codes: G08B 21/0423 detecting deviation from an expected pattern of behaviour or schedule
• CPC Class Codes: G08B 21/0476 Cameras to detect unsafe condition, e.g. video cameras
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A system and apparatus are disclosed for modeling patterns of behavior of humans or other animate objects and detecting a violation of a repetitive pattern of behavior. The behavior of one or more persons is observed over time and features of the behavior are recorded in a multi-dimensional space. Over time, the multi-dimensional data provides an indication of patterns of human behavior. Activities that are repetitive in terms of time, location and activity, such as sleeping and eating, would appear as a Gaussian distribution or cluster in the multi-dimensional data. Probability distribution functions can be analyzed using known Gaussian or clustering techniques to identify repetitive patterns of behavior and characteristics thereof, such as a mean and variance. Deviations from repetitive patterns of behavior can be detected and an alarm can be triggered, if appropriate.

Claims

1. A method for detecting an event based on behavior of an animate object, said method comprising the steps of:

obtaining a plurality of images;

recognizing at least one pattern of behavior in said image data; and

detecting an absence of said pattern of behavior.

2. The method of claim 1, wherein said detecting step further comprises the step of generating an alarm.

3. The method of claim 1, wherein said recognizing step further comprises the step of fitting a probability distribution function to said image data to identify at least one Gaussian having a mean and variance that minimizes an objective function.

4. The method of claim 3, wherein said detecting step further comprises the step of determining if features extracted from said image data exceed a predefined threshold distance based upon said variance of a Gaussian.

5. The method of claim 1, wherein said recognizing step further comprises the step of clustering said image data to identify said at least one repetitive pattern of behavior.

6. The method of claim 5, wherein said clustering step further comprises the step of computing a mean and variance of each cluster.

7. The method of claim 6, wherein said detecting step further comprises the step of determining if features extracted from said image data exceed a predefined threshold distance based upon said variance of a cluster.

8. The method of claim 6, wherein said detecting step further comprises the step of evaluating a distance between said features extracted from said image data and one of said clusters.

9. The method of claim 1, further comprising the step of extracting a plurality of features from said image data.

10. The method of claim 9, further comprising the step of expressing said plurality of extracted features as a probability distribution function.

11. The method of claim 9, further comprising the step of expressing said plurality of extracted features in a multi-dimensional space.

12. A system for detecting an event based on behavior of an animate object, said system comprising:

a memory that stores computer-readable code; and

a processor operatively coupled to said memory, said processor configured to implement said computer-readable code, said computer-readable code configured to;

obtain a plurality of images;

recognize at least one pattern of behavior in said image data; and

detect an absence of said pattern of behavior.

13. The system of claim 12, wherein said processor is further configured to generate an alarm.

14. The system of claim 12, wherein said processor is further configured to fit a probability distribution function to said image data to identify at least one Gaussian having a mean and variance that minimizes an objective function.

15. The system of claim 14, wherein said processor is further configured to determine if features extracted from said image data exceed a predefined threshold distance based upon said variance of a Gaussian.

16. The system of claim 12, wherein said processor is further configured to cluster said image data to identify said at least one repetitive pattern of behavior.

17. The system of claim 16, wherein said processor is further configured to compute a mean and variance of each cluster.

18. The system of claim 17, wherein said processor is further configured to determine if features extracted from said image data exceed a predefined threshold distance based upon said variance of a cluster.

19. The system of claim 17, wherein said processor is further configured to evaluate a distance between said features extracted from said image data and one of said clusters.

20. The system of claim 12, wherein said processor is further configured to extract a plurality of features from said image data.

21. The system of claim 20, wherein said processor is further configured to express said plurality of extracted features as a probability distribution function.

22. An article of manufacture for detecting an event based on behavior of an animate object, said article of manufacture comprising:

a computer-readable medium having computer-readable code means embodied thereon, said computer-readable program code means comprising;

a step to obtain a plurality of images;

a step to recognize at least one pattern of behavior in said image data; and

a step to detect an absence of said pattern of behavior.