INTRUSION WARNING SYSTEM

• US 20110043806A1
• Filed: 04/16/2009
• Published: 02/24/2011
• Est. Priority Date: 04/17/2008
• Status: Active Grant

• Current Assignee: Shilat Optronics Ltd.
• Original Assignee: Shilat Optronics Ltd.
• Inventors: Blai, Gil, Guetta, Avishay, Korngut, Doron
• Granted Patent: US 8,970,374 B2
• Time in Patent Office: Days
• US Class Current: 356/432
• CPC Class Codes: G01S 17/04 Systems determining the presence of a target
• CPC Class Codes: G08B 13/181 using active radiation detection systems
• CPC Class Codes: G08B 13/2491 Intrusion detection systems, i.e. where the body of an intruder causes the interference with the electromagnetic field

Abstract

A system for detecting intrusion across a surface, comprising a plurality of light sources projecting an array of illuminating beams along different optical paths in the surface and a detector array system directed such that it detects along a plurality of fields of view in the surface, illumination reflected from the illuminating beams. A signal processing system detects changes along the array of fields of view, in the reflected illumination level detected by the detector system. An increase greater than a predefined level in the reflected illumination level from any field of view provides an indication of an intrusion across the surveilled surface along that field of view, at the crossing point of the direction of that field of view with the optical path whose illuminating beam generated the increase in reflected illumination from that field of view.

Claims

1. A system for detecting intrusion, said system comprising:

an illumination source projecting an array of illuminating beams distinguished by beam identifying features, along different optical paths;

a detector array comprising elements detecting in an array of fields of view, illumination reflected from said array of illuminating beams; and

a signal processing system adapted to detect changes in the reflected illumination levels detected by said elements of said detector array,

wherein at least one of said elements of said detector array can detect reflections from more than one of said illuminating beams, and can determine which of said illuminating beams is being detected by means of said beam identifying features.

2. A system according to claim 1, wherein an increase greater than a predefined level in said reflected illumination from the field of view associated with an element provides an indication of an intrusion at the point at which said field of view associated with said element crosses said optical path whose illuminating beam generates said increase in reflected illumination from said field of view.

3. A system according to claim 2, wherein the spatial position of said crossing point at which an increase in said reflected illumination is detected is known by determining both said beam identifying feature of said reflected illumination detected and the field of view in which said change is detected.

4. A system according to claim 1, wherein said beam identifying feature is any one of:

(i) the point in time at which said illuminating beam is projected along one of said different optical paths;

(ii) a modulation feature applied differently to illuminating beams projected along different optical paths;

(iii) the wavelengths of said illuminating beams projected along different optical paths; and

(iv) the nature of the polarization of said illuminating beams projected along different optical paths.

5. A system according to claim 1, wherein said array of illuminating beams is aligned generally collinearly with said array of fields of view, such that said system provides said indication of an intrusion across a curtain-like detection plane containing said array of illuminating beams and said array of fields of view.

6. A system according to claim 1, wherein said array of illuminating beams is either (a) a plurality of parallel beams or (b) a plurality of angularly diverging beams.

8. A system according to claim 6, wherein said plurality of angularly diverging beams is projected from a single source whose beam is angularly scanned.

9. A system according to claim 1, wherein said array of illuminating beams are projected along different paths in a predetermined sequence, and said changes in the light level detected by said detector system are changes determined between successive sequences.

10. A system according to claim 1, further comprising at least one focusing element disposed to direct light reflected from different fields of view into elements of said detector system.

11. A system according to claim 1, wherein said illumination source comprises either (1) a plurality of light sources each projecting its own illuminating beam, or (2) a single source whose output is scanned angularly to generate said array of illuminating beams.

16. A system according to claim 1, and wherein said signal processing system is further adapted to detect a decrease larger than a second predetermined level, in said reflected illumination from another field of view, essentially simultaneously with said increase greater than a predetermined level in said reflected illumination from said first field of view, such that said combination of said increase and said decrease in said reflected illumination beams provides an indication of an intrusion at the crossing point of said field of view with said path whose reflected illumination shows said increase.

17. A system according to claim 1, wherein said system is rotated angularly such that it provides an indication of an intrusion in a plurality of directions of fields of view.

18. A system according to claim 17, and wherein said system provides three dimensional information regarding the location of said intrusion.

19. A system according to claim 1, wherein said illumination source projecting an array of illuminating beams is scanned in a direction generally perpendicular to said direction of projection of said array of illuminating beams, and said detector array is a two dimensional detector array directed such that different columns of said detector array detect said array of illuminating beams reflected from fields of view in directions generally perpendicular to said direction of said array of illuminating beams.

38. A system according to claim 1, wherein said signal processing system further comprises a computing module which time-sequentially determines the outputs from said elements of said detector array at a plurality of predetermined time intervals, such that a profile of a moving intruding object is generated by said time sequence.

39. A system according to claim 38, wherein said computing module utilizes output levels above a predetermined threshold level.

7. (canceled)

12-15. -15. (canceled)

20. A method for detecting intrusion, said method comprising:

projecting an array of illuminating beams distinguished by beam identifying features along a plurality of optical paths;

detecting in an array of fields of view, illumination reflected from said plurality of optical paths, the intersection of said plurality of optical paths with said array of fields of view defining crossing points; and

detecting changes in the reflected illumination levels detected in said array of fields of view,

wherein said detection in at least one field of view can detect reflections from more than one of said illuminating beams, and can determine which of said illuminating beams is being detected by means of said beam identifying features.

21. A method according to claim 20, wherein an increase greater than a predetermined level in said reflected illumination originating from any of said crossing points provides an indication of an intrusion at said crossing point.

22. A method according to claim 21, wherein the spatial position of a crossing point at which an increase in said reflected illumination is revealed is known by determining both the beam identifying feature of the reflected illumination detected and the field of view in which said change is detected.

23. A method according to claim 21, wherein said beam identifying feature is any one of:

(i) the point in time at which illumination is projected along one of said plurality of optical paths;

(ii) a modulation feature applied differently to illumination projected along different ones of said plurality of optical paths;

(iii) the wavelength of said illumination projected along different ones of said plurality of optical paths; and

(iv) the nature of the polarization of said illumination projected along different ones of said plurality of optical paths.

24. A method according to claim 20, wherein said plurality of optical paths are distinguished either laterally or angularly.

26. A method according to claim 20, wherein said illumination projected along different paths originates from either a plurality of sources or a single angularly scanned source.

28. A method according to claim 20, further comprising the step of aligning said plurality of optical paths generally collinearly with said array of fields of view, such that said method provides said indication of an intrusion across a curtain-like detection plane containing said plurality of optical paths and said array of fields of view.

29. A method according to claim 20, wherein said crossing points are predefined to eliminate regions where spurious signals are expected.

31. A method according to claim 20, wherein each of said fields of view is distinguished by means of detector elements adapted to detect illumination originating from said array of fields of view, and said crossing point from which said reflected illumination originates is determined by knowledge of which of said detector elements is associated with said field of view and which of said array of illuminating beams gives rise to said increased reflected illumination detected by said detector element.

32. A method according to claim 20, further comprising the step of determining a decrease larger than a second predetermined level, of reflected illumination originating from another of said crossing points, essentially simultaneously with said increase above a predetermined level in said reflected illumination originating from said first crossing point, wherein said combination of said increase and said decrease in said reflected illumination provides an indication of a suspected intrusion across said surface at said crossing point where said increase in said reflected illumination is determined.

33. A method according to claim 20, further comprising the step of angularly rotating said plurality of optical paths such that it provides an indication of an intrusion in a plurality of directions of fields of view.

34. A method according to claim 33, said method providing three dimensional information regarding the location of said intrusion.

35. A method according to claim 20, further comprising the step of scanning said illumination projected along a plurality of optical paths in a direction generally perpendicular to said direction of said plurality of optical paths, such that said illumination reflected from said array of fields of view is detected in two dimensions.

40. A method according to claim 20, further comprising the steps of:

determining the outputs from'"'"'the elements of said detector array;

repeating said determining at a plurality of predetermined time intervals; and

generating from said repeated determinations a profile of a moving intruding object.

41. A method according to claim 40 wherein said determining of the outputs utilizes output levels above a predetermined threshold level.

25. (canceled)

27. (canceled)

30. (canceled)

36. (canceled)

37. A system for detecting intrusion, said system comprising:

at least one source projecting an array of illuminating beams along different optical paths;

a detector system directed such that it detects in a field of view, illumination reflected from said illuminating beams; and

a signal processing system adapted to detect changes in said field of view, of the reflected illumination level detected by said detector system,

wherein an increase greater than a predefined level detected in said reflected illumination level from said field of view provides an indication of an intrusion in said field of view, at the crossing point of said field of view with said optical path whose reflected illumination shows said increase.