Near-infrared disguise detection

• US 20030169901A1
• Filed: 12/03/2002
• Published: 09/11/2003
• Est. Priority Date: 09/03/1999
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Fritz, Bernard S., Pavlidis, Ioannis, Symosek, Peter F.
• Granted Patent: US 6,718,049 B2
• Time in Patent Office: Days
• US Class Current: 382/103
• CPC Class Codes: G06V 10/143 Sensing or illuminating at different wavelengths
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G06V 40/161 Detection; Localisation; Normalisation

Abstract

Detection of a person disguised with one or more artificial materials includes detecting reflection from at least one portion of a head of a human body in at least a portion of an upper band of the near infrared spectrum. The presence of an artificial material associated with the head of the human body is determined based on the detected reflection.

Claims

1. A method for use in detection of a person disguised with one or more artificial materials, the method comprising:

detecting reflection from at least one portion of a head of a human body in at least a portion of an upper band of the near infrared spectrum; and

determining the presence of an artificial material associated with the head of the human body based on the detected reflection.

2. The method of claim 1, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m and above in upper band of the near infrared spectrum.

3. The method of claim 2, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m to 2.4 μ

m in the upper band of the near infrared spectrum.

4. The method of claim 3, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m to 1.7 μ

m in the upper band of the near infrared spectrum.

5. The method of claim 1, wherein detecting reflection comprises detecting reflection from at least a skin portion of the head of the human body.

6. The method of claim 1, wherein detecting reflection comprises detecting reflection from at least a hair portion of the head of the human body.

7. The method of claim 1, wherein determining the presence of an artificial material associated with the head of the human body comprises displaying to a user a representation of the detected reflection of the at least one portion of the head of the human body.

8. The method of claim 1, wherein determining the presence of an artificial material associated with the head of the human body comprises:

generating data representative of the detected reflection; and

comparing the data to at least one threshold reference reflection level.

9. The method of claim 8, wherein generating data representative of the detected reflection comprises focusing the reflection on a pixel array that is sensitive to the at least a portion of the upper band of the near infrared spectrum, and generating a signal representative of the spectral power for each of a plurality of pixels of the pixel array to be used for the comparison to the at least one threshold reference reflection level.

10. The method of claim 8, wherein the at least one threshold reference reflection level is based on a level of reflection of the one or more artificial materials.

11. The method of claim 10, wherein the at least one threshold reference reflection level is a plurality of reference reflection levels corresponding to a plurality of artificial materials, and further wherein the method comprises identifying one or more of the artificial materials associated with the head of the human body.

12. The method of claim 8, wherein the at least one threshold reference reflection level is based on a level of reflection of natural skin of the human body.

13. The method of claim 8, wherein the at least one threshold reference reflection level is based on a level of reflection of natural hair of the human body.

14. The method of claim 1, wherein the method further comprises illuminating the at least a portion of the head of the human body using an illumination source matched to the at least a portion of the upper band of the near infrared spectrum.

15. The method of claim 14, wherein the method further comprises:

detecting an illumination level proximate the head of the human body; and

controlling the illumination source based on the detected illumination level to maintain a desired illumination level on the head of the human body.

16. A disguised person detection system comprising:

a detector apparatus operable to detect reflection from at least a portion of a head of a human body in at least a portion of an upper band of the near infrared spectrum; and

an indication apparatus operable to provide a user with information as to the presence of an artificial material associated with the head of the human body based on the detected reflection.

17. The system of claim 16, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m and above in the upper band of the near infrared spectrum.

18. The system of claim 17, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m to 2.4 μ

m in the upper band of the near infrared spectrum.

19. The system of claim 18, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m to 1.7 μ

m in the upper band of the near infrared spectrum.

20. The system of claim 16, wherein the indication apparatus comprises a display operable to provide a representation of the detected reflection of the at least the portion of the head of the human body.

21. The system of claim 16, wherein the system further comprises a display operable to provide a representation of the detected reflection of the at least the portion of the head of the human body for use in presenting the information as to the presence of an artificial material associated with he head of the human body.

22. The system of claim 16, wherein the detector apparatus comprises one or more pixels sensitive to the at least a portion of the upper band of the near infrared spectrum and operable to provide information representative of the detected reflection from the at least the portion of the head of the human body, and further wherein the indication apparatus comprises circuitry operable to compare the information representative of the detected reflection to at least one threshold reference reflection level.

23. The system of claim 22, wherein the at least one threshold reference reflection level is based on a level of reflection of the one or more artificial materials.

24. The system of claim 23, wherein the at least one threshold reference reflection level is a plurality of reference reflection levels corresponding to a plurality of artificial materials, and further wherein the circuitry of the indication apparatus is operable for use in identifying one or more of the artificial materials associated with the head of the human body.

25. The system of claim 22, wherein the at least one threshold reference reflection level is based on a level of reflection of natural skin of the human body.

26. The system of claim 22, wherein the at least one threshold reference reflection level is based on a level of reflection of natural hair of the human body.

27. The system of claim 16, wherein the system further comprises an illumination source matched to the at least a portion of the upper band of the near infrared spectrum positioned to illuminate the at least the portion of the head of the human body.

28. The system of claim 27, wherein the system further comprises a detector operable to detect an illumination level proximate the head of the human body, and further wherein the indication apparatus comprises circuitry operable to control the illumination source based on the detected illumination level to maintain a desired illumination level of the head of the human body.

29. A detection method comprising:

detecting reflection from a scene in at least a portion of one band of the near infrared spectrum;

determining the presence of a head of a human body in the scene based on the detected reflection in the at least a portion of the one band of the near infrared spectrum;

detecting reflection from at least one portion of the head of the human body in at least a portion of an upper band of the near infrared spectrum to determine the presence of an artificial material associated with the head of the human body based on the detected reflection from at least one portion of the head of the human body.

30. The method of claim 29, wherein detecting reflection from a scene in at least a portion of one band of the near infrared spectrum comprises detecting reflection from the scene in at least a portion of a lower band of the near infrared spectrum and from the scene in at least a portion of an upper band of the near infrared spectrum.

31. The method of claim 30, wherein the at least a portion of the lower band of the near infrared spectrum is at least a portion within the range of 0.8 ∥

m to 1.4 μ

m in the lower band of the near infrared spectrum, and further wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m to 2.2 μ

m in the upper band of the near infrared spectrum.

32. The method of claim 29, wherein detecting reflection from a scene in at least a portion of one band of the near infrared spectrum comprises detecting reflection from the scene in at least a portion of the upper band of the near infrared spectrum.

33. The method of claim 32, wherein the at least a portion of the upper band of the near infrared spectrum is at least a portion within the range of 1.4 μ

m to 2.2 μ

m in the upper band of the near infrared spectrum.

34. The method of claim 29, wherein detecting reflection from at least one portion of a head of a human body in at least a portion of an upper band of the near infrared spectrum comprises detecting reflection from at least one portion of a head of a human body in at least a portion within the range of 1.4 μ

m to 2.2 μ

m in the upper band of the near infrared spectrum.

35. The method of claim 29, wherein detecting reflection from at least one portion of a head of a human body comprises detecting reflection from at least a skin portion of the head of the human body.

36. The method of claim 29, wherein detecting reflection from at least one portion of a head of a human body comprises detecting reflection from at least a hair portion of the head of the human body.

37. The method of claim 34, wherein to determine the presence of an artificial material associated with the head of the human body a representation of the detected reflection of the at least one portion of the head of the human body is displayed to a user.

38. A detection system for use in detecting a human in a scene, the detection system comprising:

a first camera sensitive to a first band of wavelengths within a reflected infrared radiation range and operable to provide one or more frames of a first image output representative of the scene;

a second camera sensitive to a second band of wavelengths within the reflected infrared radiation range and operable to provide one or more frames of a second image output representative of the scene;

an optical device positioned to direct light reflected from the scene in at least the first band of wavelengths to the first camera and to direct light reflected from the scene in at least the second band of wavelengths to the second camera, wherein the one or more frames of the first image output are co-registered in time with the one or more frames of the second image output; and

a processing apparatus operable to detect a human in the scene based on the first and second image outputs.

39. The system of claim 38, wherein the optical device comprises a combination beamsplitter and filter.

40. The system of claim 39, wherein the optical device is an optical component having a coating thereon that directs light with wavelengths below about 1.4 microns to the first camera and light with wavelengths above about 1.4 microns to the second camera.

41. The system of claim 38, wherein the processing apparatus is operable to fuse spectral power of the pixels of the first image output with spectral power of corresponding pixels of the second image output to provide a fused image output having an increased contrast between a human and a background in the scene.

42. The system of claim 41, wherein the processing apparatus is further operable to segment the human from the scene by comparing the spectral power of each pixel of the fused image output to one or more threshold values.

43. The system of claim 38, wherein a difference in reflectance for human skin in the first band of wavelengths relative to the second band of wavelengths is greater than a difference in reflectance for objects other than human skin in the first band of wavelengths relative to the second band of wavelengths.

44. The system of claim 38, wherein the processing apparatus is further operable to perform a weighted difference calculation of spectral power of the pixels of the first image output with spectral power of corresponding pixels of the second image output resulting in a weighted difference output for the pixels.

45. The system of claim 44, wherein the processing apparatus is further operable to compare the weighted difference output for the pixels to one or more threshold values to differentiate pixels representative of human skin from pixels representative of objects other than human skin.

46. The system of claim 38, wherein said first and second cameras have the same fields-of-view.

47. A detection system comprising:

first camera means for sensing radiation of a scene within a first band of wavelengths in a reflected infrared radiation range and operable to provide one or more frames of a first image output representative of the scene;

second camera means for sensing radiation of the scene within a second band of wavelengths in the reflected infrared radiation range and operable to provide one or more frames of a second image output representative of the scene;

optical device means positioned for directing light reflected from the scene in at least the first band of wavelengths to the first camera means and for directing light reflected from the scene in at least the second band of wavelengths to the second camera means such that one or more frames of the first image output are co-registered in time with one or more frames of the second image output; and

processing means for detecting a human in the scene based on the first and second image outputs.

48. The system of claim 47, wherein the processing means comprises:

fusing means connected to said first and second camera means for fusing spectral powers P(i,j)₁ of pixels (i,j)₁ from said first camera means with spectral powers P(i,j)₂ of corresponding pixels (i,j)₂ from said second camera means, resulting in fused spectral powers P(i,j)_f; and

thresholding means, connected to said fusing means, for thresholding fused spectral powers P(i,j)_f from said fusing means, resulting in threshold spectral powers P(i,j)_t; and

wherein;

the scene is focused by said first camera means on a first sensing array having m×

n pixels;

the scene is focused by said second camera means on a second sensing array having m×

n pixels;

each pixel is located at ith row and jth column;

0≦

i≦

m; and

0<

j≦

n.

49. The system of claim 48, further comprising indicating means for displaying a segmented image of the scene.

50. The system of claim 49, wherein:

P(i,j)_f=P(i,j)₁−

C*P(i,j)₂; and

C is a constant determined according to a lighting condition of the scene.

51. The system of claim 50, wherein:

P(i,j)₁=V₁ if P(i,j)_f>

T;

P(i,j)_t=V₂ if P(i,j)_f<

T;

V₁ is a first value;

V₂ is a second value; and

T is a threshold value, wherein T is determined by a spectral power distribution of fused pixels (i,j)_f.

52. The system of claim 47, wherein a wavelength between the first and second bands of wavelengths is about 1.4 microns.

53. The system of claim 47, wherein:

the first band of wavelengths is between about 0.8 and 1.4 microns; and

the second band of wavelengths is between about 1.4 microns and 2.2 microns.

54. A method for detecting humans, comprising:

focusing a scene on a first m x n pixel array that is sensitive to light of a first bandwidth within a reflected infrared radiation range resulting in one or more frames of a first image output representative of the scene and on a second m×

n pixel array that is sensitive to light of a second bandwidth within the reflected infrared radiation range resulting in one or more frames of a second image output representative of the scene;

co-registering one or more frames of the first image output with one or more frames of the second image output, wherein co-registering the frames comprises using an optical device to direct light reflected from the scene in at least the first bandwidth to the first m×

n pixel array at each of a plurality of points in time and directing light reflected from the scene in at least the second bandwidth to the second m×

n pixel array at each of the plurality of points in time; and

using the first and second image outputs to detect a human in the scene.

55. The method of claim 54, wherein using the first and second image outputs to detect a human in the scene comprises fusing spectral power of the pixels of the first image output with spectral power of corresponding pixels of the second image output to provide a fused image output having an increased contrast between a human and a background in the scene.

56. The method of claim 55, wherein using the first and second image outputs to detect a human in the scene further comprises segmenting the human from the scene by comparing the spectral power of each pixel of the fused image output to one or more threshold values.

57. The method of claim 56, wherein the method further comprises displaying a segmented image.

58. The method of claim 54, wherein a wavelength between the first and second bandwidths is about 1.4 microns.

59. The method of claim 54, wherein the first bandwidth is between about 0.8 and 1.4 microns and the second bandwidth is between about 1.4 microns and 2.2 microns.

60. The method of claim 54, wherein a difference in reflectance for human skin in the first bandwidth relative to the second bandwidth is greater than a difference in reflectance for objects other than human skin in the first bandwidth relative to the second bandwidth.

61. The method of claim 54, wherein using the first and second image outputs to detect a human in the scene comprises performing a weighted difference calculation of spectral power of the pixels of the first image output with spectral power of corresponding pixels of the second image output resulting in a weighted difference output for the pixels.

62. The method of claim 61, wherein using the first and second image outputs to detect a human in the scene further comprises comparing the weighted difference output for the pixels to one or more threshold values to differentiate pixels representative of human skin from pixels representative of objects other than human skin.

63. The method of claim 54, wherein using the first and second image outputs to detect a human in the scene comprises:

fusing a spectral power P(i,j)₁ of each pixel of the first m×

n pixel array with a spectral power P(i,j)₂ of each corresponding pixel of the second m×

n pixel array, to result in a spectral power P(i,j)_f of a fused pixel, respectively;

thresholding the spectral power P(i,j)_f of each fused pixel into a first value if the spectral power is greater than a threshold value; and

thresholding the spectral power P(i,j)_f of each fused pixel into a second value if the spectral power is less than the threshold value;

wherein;

0<

i≦

m; and

0<

j≦

n.

64. The method of claim 63, wherein:

P(i,j)_f=P(i,j)₁−

C*P(i,j)₂; and

C is a constant dependent upon a lighting condition of the scene.

65. The method of claim 64, wherein:

P(i,j)_t=V₁ if P(i,j)_f>

T;

P(i,j)_t=V₂ if P(i,j)_f<

T;

V₁ is a first value;

V₂ is a second value; and

T is a threshold value dependent upon a distribution of spectral powers P(i,j)_f of the fused pixels.