Tracking and monitoring system

• US 20010006367A1
• Filed: 12/13/2000
• Published: 07/05/2001
• Est. Priority Date: 12/27/1999
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Oda, Naoki
• Granted Patent: US 6,498,564 B2
• Time in Patent Office: Days
• US Class Current: 340/567
• CPC Class Codes: G08B 13/19 using infrared-radiation detection systems G08B13/194 takes precedence

Abstract

A tracking and monitoring system directs an infrared sensor toward a heat source such as a human body, and three-dimensionally tracks the heat source, wherein the infrared sensor has four infrared detecting elements appropriately located with respect to a reference point in the field of view for producing respective detecting signals varied in magnitude depending upon the parts of the image of heat source incident on the four infrared detecting elements so that a wired logic circuit controls the attitude of the infrared sensor in such a manner as catch the image of the heat source at the reference point.

Claims

1. A tracking and monitoring system comprising

a heat source tracker producing a data signal representative of a current position of said heat source in a field of view and three-dimensionally changing the attitude thereof in such a manner as to catch an image of said heat source at a predetermined position in said field of view for tracking said heat source in a monitoring zone,

a data processing system connected to said heat source tracker, checking said data signal to see whether or not said heat source enters a prohibited zone defined in said monitoring zone and producing an instruction for an alarm when said heat source enters said prohibited zone, and

an alarm unit connected to said data processing system and responsive to said instruction for giving said alarm.

2. The tracking and monitoring system as set forth in

claim 1

, in which said data processing system selectively establishes a search mode and a tracking mode in said heat source tracker, said heat source tracker searches said monitoring zone for said heat source in said search mode while said data processing system does not find any heat source in said monitoring zone, and tracks said heat source in said tracking mode while said heat source is being moved in said monitoring zone.

3. The tracking and monitoring system as set forth in

claim 1

, in which said heat source tracker is sensitive to infrared light ranging from 2 micron wavelength to 14 micron wavelength.

4. The tracking and monitoring system as set forth in

claim 1

, in which said heat source tracker has plural infrared detecting elements receiving infrared light radiated from said heat source and producing detecting signals each representative of the amount of infrared light incident on associated one of said plural infrared detecting elements, a wired logic circuit connected to said plural infrared detecting elements and producing driving signals representative of said current position of said heat source offset from said predetermined position, and an actuator connected to said plural infrared detecting elements and responsive to said driving signals for changing said attitude thereof.

5. The tracking and monitoring system as set forth in

claim 4

, in which said plural infrared detecting elements are located in four quadrants defined in said field of view by two virtual axes perpendicular to each other, and said wired logic circuit compares the detecting signals supplied from the infrared detecting elements on one side of one of said virtual axes with the detecting signals supplied from the infrared detecting elements on the other side of said one of said virtual axes for producing one of said driving signals representative of an offset from said one of said virtual axes, and the detecting signals supplied from the infrared detecting elements on one side of the other of said virtual axes with the detecting signals supplied from the infrared detecting elements on the other side of said other of said virtual axes for producing the other of said driving signals representative of an offset from said other of said virtual axes.

6. The tracking and monitoring system as set forth in

claim 5

, in which said wired logic circuit includes a first comparator supplied with said detecting signals for producing said one of said driving signals and a second comparator supplied with said detecting signals for producing said other of said driving signals.

7. The tracking and monitoring system as set forth in

claim 5

, in which said wired logic circuit further includes plural adders connected between said plural infrared detecting elements and said first and second comparators, and selectively supplied with said detecting signals for eliminating a noise component from said detecting signals.

9. The tracking and monitoring system as set forth in

claim 1

, further comprising a display unit connected to said data processing system and responsive to an image-carrying signal representative of a trajectory of said heat source for producing an image of said trajectory.

10. The tracking and monitoring system as set forth in

claim 9

, in which said image-carrying signal further representative of a scene in said monitoring zone stored in said data processing system so that said display unit produces an image of said scene in such a manner as to overlap said image of said trajectory with said image of said scene.

11. The tracking and monitoring system as set forth in

claim 1

, in which said data processing system automatically determines said prohibited zone in said monitoring zone when said data processing system receives a piece of data representative of a certain position on an access way through which said heat source is to enter into said monitoring zone.

12. The tracking and monitoring system as set forth in

claim 1

, further comprising a lighting system for radiating visual light.

13. The tracking and monitoring system as set forth in

claim 12

, in which said visual light is directed to said prohibited zone.

14. The tracking and monitoring system as set forth in

claim 13

, in which said data processing system instructs said lighting system to radiate said visual light to said prohibited zone when said heat source enters said prohibited zone.

15. The tracking and monitoring system as set forth in

claim 14

, in which said lighting system is attached to said heat source tracker so that said visual light goes run after said heat source after the entry into said prohibited zone.

16. The tracking and monitoring system as set forth in

claim 1

, further comprising a camera for taking pictures of said heat source and an image producing and storing system connected between said data processing system and said camera, responsive to an instruction supplied from said data processing unit for causing said camera to take pictures and storing pieces of image data representative of said pictures in a memory.

17. The tracking and monitoring system as set forth in

claim 16

, in which said data processing system instructs said image producing and storing system to take said pictures when said heat source enters said prohibited zone.

18. The tracking and monitoring system as set forth in

claim 17

, in which said camera is attached to said heat source tracker so that said camera is directed to said heat source after the entry into said prohibited zone.

19. The tracking and monitoring system as set forth in

claim 17

, in which the resolution of said camera is so high that looks of said heat source is discriminative from said pictures.

20. The tracking and monitoring system as set forth in

claim 16

, further comprising an infrared light projector connected to said image producing and storing system for projecting infrared light toward said heat source when said camera takes said pictures.

21. The tracking and monitoring system as set forth in

claim 20

, in which said infrared light projector and said camera are attached to said heat source tracker.

8. The tracking and monitoring system as set forth in 4, in which said plural infrared detecting elements are located on four virtual lines extending from said predetermined position at intervals of 90 degrees, and said wired logic circuit compares the detecting signals supplied from the infrared detecting elements on the two virtual lines aligned with each other for producing one of said driving signals representative of an offset from the other virtual lines perpendicular to said two virtual lines, and the detecting signals supplied from the infrared detecting elements on said other virtual lines for producing the other of said driving signals representative of an offset from said two virtual lines.