Video surveillance system that detects predefined behaviors based on movement through zone patterns

• US 20050104727A1
• Filed: 08/12/2004
• Published: 05/19/2005
• Est. Priority Date: 11/17/2003
• Status: Active Grant

• Current Assignee: Axis AB (Canon Inc.)
• Original Assignee: Vidient Systems, Inc. (Agilence Incorporated)
• Inventors: Gong, Yihong, Han, Mei, Tao, Hai
• Granted Patent: US 7,088,846 B2
• Time in Patent Office: Days
• US Class Current: 340/541
• CPC Class Codes: G06V 40/20 Movements or behaviour, e.g. gesture recognition recognition of facial expressions G06V40/16
• 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 13/19608 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 13/19615 wherein said pattern is defined by the user
• CPC Class Codes: G08B 13/19652 Systems using zones in a single scene defined for different treatment, e.g. outer zone gives pre-alarm, inner zone gives alarm

Abstract

A video surveillance system uses rule-based reasoning and multiple-hypothesis scoring to detect predefined behaviors based on movement through zone patterns. Trajectory hypothesis spawning allows for trajectory splitting and/or merging and includes local pruning to managed hypothesis growth. Hypotheses are scored based on a number of criteria, illustratively including at least one non-spatial parameter. Connection probabilities computed during the hypothesis spawning process are based on a number of criteria, illustratively including object size. Object detection and probability scoring is illustratively based on object class.

Claims

1. A method for use in a video surveillance system, the method comprising

generating at least one hypothesis comprising a set of hypothesized trajectories of objects identified, based on their appearance, as being in a particular object class and hypothesized to have been moving through an area under surveillance at a particular time, said area under surveillance being divided into at least two zones,

utilizing said hypothesis to determine whether at least one predefined alert condition has occurred within the area under surveillance, said at least one alert condition including a predetermined pattern of movement of at least one of said objects between at least two of said zones.

2. The method of claim 1 wherein said area under surveillance includes a door, wherein at least one of said zones is a door zone that includes said door, and wherein said predetermined pattern of movement includes movement of said at least one object a) from said door zone to another one of said zones, or b) to said door zone from another one of said zones.

3. The method of claim 2 wherein the determination of whether said alert condition has occurred is made independent of any non-video signal indicating the open or closed status of said door.

4. The method of claim 1 wherein said area under surveillance includes an access control device, wherein at least one of said zones is an access entry zone that includes said access control device, and wherein said predetermined pattern of movement includes movement of said at least one object a) from said access entry zone to another one of said zones, or b) to said access entry zone from another one of said zones.

5. The method of claim 4 wherein the determination of whether said alert condition has occurred is made independent of any non-video signal indicating that said access control device has been used.

6. The method of claim 4 wherein said area under surveillance further includes a normally locked door, wherein said access control device is operative to cause said door to become unlocked, wherein at least one of said zones is a door zone that includes said door, and wherein said predetermined pattern of movement further includes movement of said at least one object a) from said door zone to another one of said zones, or b) to said door zone from another one of said zones.

7. The method of claim 1 wherein said area under surveillance is one of a) a secure area into which objects enter from a non-secure area and b) a non-secure area from which objects enter into a secure area.

8. The method of claim 7 wherein said area under surveillance includes a normally locked door separating said secure area from said non-secure area, wherein at least one of said zones is a door zone that includes said door, and wherein said predetermined pattern of movement includes movement of said at least one object a) from said door zone to another one of said zones, or b) to said door zone from another one of said zones.

9. The method of claim 8 wherein the determination of whether said alert condition has occurred is made independent of any non-video signal indicating the open or closed status of said door.

10. The method of claim 9 wherein at least one of said secure area and said non-secure area includes an access control device operative to cause said door to become unlocked.

11. The method of claim 10 wherein said access control device is located in the area under surveillance, wherein at least one of said zones is an access entry zone that includes said access control device, and wherein said predetermined pattern of movement includes movement of said at least one object a) from said access entry zone to another one of said zones, or b) to said access entry zone from another one of said zones.

12. The method of claim 11 wherein the determination of whether said alert condition has occurred is made independent of any non-video signal indicating that said access control device has been used.

13. The invention of claim 1 wherein said predetermined pattern of movement further includes a predetermined pattern of movement of at least one other object within the area under surveillance.

14. The invention of claim 1 wherein said predetermined pattern of movement further includes a predetermined time relationship of the movements of one or more of said objects relative to at least one of a) at least one other moving object, b) one or more fixed objects, or c) one of more of said zones.

17. An electronic surveillance system adapted to carry out the method defined by claim 1.

18. A tangible medium on which are stored instructions that are executable by a processor to carry out the method defined by claim 1.

15. A method for use in a video surveillance system, the method comprising

generating at least one hypothesis comprising a set of hypothesized trajectories of objects identified, based on their appearance, as being in a particular object class and hypothesized to have been moving through an area under surveillance at a particular time, said area under surveillance being divided into at least two zones,

utilizing said at least said one of said hypotheses to determine whether at least one predefined alert condition has occurred within the area under surveillance, said at least one alert condition including a predetermined pattern of movement of at least one of said objects relative to at least one of said zones.

16. The method of claim 15 wherein said predetermined pattern of movement includes the presence of said at least one of said objects within said at least one of said zones for more than a predetermined period of time.

19. An electronic surveillance system adapted to carry out the method defined by claim 15.

20. A tangible medium on which are stored instructions that are executable by a processor to carry out the method defined by claim 15.