Method, Apparatus and System for Rapid and Sensitive Standoff Detection of Surface Contaminants

• US 20070222981A1
• Filed: 03/20/2007
• Published: 09/27/2007
• Est. Priority Date: 03/22/2006
• Status: Active Grant

• Current Assignee: Peraton, Inc.
• Original Assignee: ITT Manufacturing Enterprises, Inc. (ITT, Inc.)
• Inventors: Rezac, Jeromy, Kletecka, Christopher, Ponsardin, Patrick
• Granted Patent: US 7,796,251 B2
• Time in Patent Office: Days
• US Class Current: 356/301
• CPC Class Codes: G01J 3/02 Details
• CPC Class Codes: G01J 3/0218 using optical fibers
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/0291 Housings; Spectrometer accessories; Spatial arrangement of elements, e.g. folded path arrangements
• CPC Class Codes: G01J 3/44 Raman spectrometry; Scattering spectrometry ; Fluorescence spectrometry
• CPC Class Codes: G01N 21/65 Raman scattering
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held

Abstract

Systems and methods for fast and sensitive standoff surface-hazard detection with high data throughput, high spatial resolution and high degree of pointing flexibility. The system comprises a first hand-held unit that directs an excitation beam onto a surface that is located a distance away from the first unit and an optical subsystem that captures scattered radiation from the surface as a result of the beam of light. The first unit is connected via a link that includes a bundle of optical fibers, to a second unit, called the processing unit. The processing unit comprises a fiber-coupled spectrograph to convert scattered radiation to spectral data, and a processor that analyzes the collected spectral data to detect and/or identify a hazardous substance. The second unit may be contained within a body-wearable housing or apparatus so that the first unit and second unit together form a man-portable detection assembly. In one embodiment, the system can continuously and without interruptions scan a surface from a 1-meter standoff while generating Raman spectral-frames at rates of 25 Hz.

Claims

1. A standoff hazard detection and identification system capable of detecting and identifying contaminants on a surface, comprising:

a. a first unit that emits a beam of monochromatic light onto a surface that is located a distance away from the first unit and captures scattered radiation from said surface as a result of said beam of monochromatic light;

b. a second unit comprising a spectrograph that converts said scattered radiation to spectral data, and a processor that analyzes the spectral data in order detect a contaminant on said surface; and

c. a link between said first unit and said second unit to couple said scattered radiation from said first unit to said second unit

2. The system of claim 1, wherein said first unit is a portable hand-held device and comprises a monochromatic light source that produces the beam of monochromatic light.

3. The system of claim 1, wherein said monochromatic light source is an ultraviolet (UV) laser.

4. The system of claim 1, wherein said second unit comprises a monochromatic light source that generates said beam of monochromatic light, and wherein said link comprises an optical fiber that supplies said beam to said first unit.

5. The system of claim 1, wherein said first unit comprises a collection optics subsystem that collects said scattered radiation from said surface for coupling via said link to said second unit.

6. The system of claim 5, wherein said first unit comprises a visible target indicator that emits a plurality of beams of visible light through said collection optics subsystem so that the plurality of beams intersect each other on said surface at a focal point of said collection optics subsystem.

7. The system of claim 6, wherein said visible target indicator comprises at least two laser diodes mounted on a housing of said first unit and positioned such that their beams intersect each other on said surface at a focal point of said collection optics subsystem.

8. The system of claim 1, wherein said monochromatic light source generates said beam of monochromatic light in the ultraviolet (UV) spectrum to induce substances on said surface to emit Raman scattered radiation from said surface.

9. The system of claim 8, wherein said processor compares said spectral data to a plurality of spectral data of known substances, and determines whether said substance is a known or foreign substance.

10. The system of claim 8, wherein said first unit is moved across the surface in order to scan the surface at a scanning rate up to tens of centimeters per second.

11. The system of claim 1, wherein said monochromatic light source generates said beam of monochromatic light so as to illuminate a spot that is less than one millimeter in diameter.

12. The system of claim 1, wherein said second unit further comprises a pixelated detector that generates a measurement frame comprising one or an accumulation of a plurality of returns of scattered radiation from said surface.

13. The system of claim 12, wherein said second unit generates data at a rate of more than 10 measurement frames per second.

14. The system of claim 12, wherein the processor adjusts said rate by adjusting a number of the plurality of returns of scattered radiation to be accumulated for a measurement frame.

15. The system of claim 14, wherein the processor controls said second unit to operate in one of first and second modes of operation, where in the first mode, the pixelated detector accumulates a relatively small number of returns of scattered radiation for a measurement frame to provide a higher rate for faster scanning on said surface and lower fidelity analysis, and in the second mode, the pixelated detector accumulates a relatively high number of returns of scattered radiation for a measurement frame to provide a slower rate for slower scanning on said surface and higher fidelity analysis.

16. The system of claim 1, wherein said first unit comprises a collection optics subsystem that collects said scattered radiation from said surface for coupling via said link to said second unit, wherein said collection optics subsystem comprises one or more optical elements that are movable to adjust a focal point of said collection optics subsystem. SPEC

17. A coordinated hazard detection and identification system, comprising:

a. a plurality of hazard detectors that are capable of detecting contaminants on a surface by emitting a beam of light onto a surface, capturing scattered radiation from the surface as a result of said beam of light, converting the scattered light to spectral data, and analyzing the spectral data to produce detection and identification data related to hazard substances or contaminants; and

b. a central control station wirelessly linked to the plurality of hazard detectors, wherein said central control station receives detection and identification data from said plurality of hazard detectors and transmits control signals to the plurality of hazard detectors in order to coordinate a detection sweep of surfaces in a region of interest.

18. The system of claim 17, wherein each of the plurality of hazard detectors are standoff hazard detectors each of which comprises a first unit that emits a beam of monochromatic light onto the surface that is located a distance away from the first unit and captures scattered radiation from said surface as a result of said beam of monochromatic light, a second unit comprising a spectrograph that converts said scattered radiation to spectral data, and a processor that analyzes the spectral data in order detect a contaminant on said surface, and a link between said first unit and said second unit to couple said scattered radiation from said first unit to said second unit

19. A standoff hazard detection and identification system capable of detecting and identifying contaminants on a surface from a distance, comprising:

a. a first unit comprising a monochromatic light source that emits a beam of light onto a surface that is located a distance away from the first unit and an optical subsystem that captures scattered radiation from said surface as a result of said beam of monochromatic light;

b. a second unit coupled to said first unit comprising a spectrograph that converts said scattered radiation to spectral data and a processor that analyzes said spectral data in order to detect a contaminant on said surface, said second unit comprising a transceiver capable of transmitting said spectral data to another device for processing; and

c. a third unit comprising a transceiver that receives said spectral data from said second unit and a processor that analyzes said spectral data with one or more algorithms that are more computationally intensive than algorithms used by the processor in said second unit.

21. The system of claim 20, wherein said third unit transmits via said transceiver to said second unit results of analysis performed by said third unit.

22. The system of claim 21, wherein said second unit comprises a user interface and display to display said results.

23. The system of claim 20, wherein the transceivers in the second unit and the transceivers in the third unit are wireless transceiver devices.

24. The system of claim 20, wherein second unit comprises a rechargeable power supply, and said third unit comprises a docking port to connect to said second unit in order to exchange information with said second unit, and for supplying electrical energy to charge said rechargeable power supply chargeable batteries of said second unit.

25. A standoff hazard detection system, comprising:

a. a light source that emits a beam of light onto a surface to excite Raman scattered radiation from said surface;

b. an optical subsystem that collects the Raman scattered radiation;

c. a spectrograph that receives the Raman scattered radiation collected by said optical subsystem and generates a measurement frame of Raman spectral data based on an accumulation of a plurality of returns of Raman scattered radiation from said surface; and

d. a processor that analyzes the Raman spectral data using Raman spectroscopy techniques to discriminate substances on said surface, wherein the processor analyzes the Raman spectral data at a sample rate of at least ten measurement frames per second.

26. A method for standoff detection of a hazardous substance, comprising:

a. in a first hand-held unit, directing a light beam to a surface located a distance away from the first unit;

b. in said first unit, capturing returned scattered radiation from said surface as a result of interaction of the light beam with a substance on said surface;

c. coupling said returned scattered radiation to a second unit separate from said first unit;

d. generating spectral data from said returned scattered radiation in said second unit; and

e. analyzing said spectral data to detect a contaminant on said surface.

27. The method of claim 26, wherein said analyzing is performed in said second unit.

28. The method of claim 26, and further comprising wirelessly transmitting said spectrum data from said second unit to a third unit positioned remotely from said second unit, and wherein said analyzing is performed in said third unit.

29. The method of claim 26, wherein said (d) generating comprises generating a measurement frame of spectral data comprising one or an accumulation of a plurality of returns of scattered radiation from said surface.

30. The method of claim 26, wherein in a first mode, said (d) generating comprises generating said spectral data from accumulation of a relatively small number of returns of scattered radiation for a measurement frame for a faster scanning across said surface and a lower fidelity analysis, and in a second mode, said (d) generating comprises generating said spectral data from accumulation of a relatively high number of returns of scattered radiation for a measurement frame for slower scanning across said surface and a higher fidelity analysis.

31. A man-portable standoff hazard detection apparatus, comprising:

a. a hand-held unit that directs a light beam onto a surface located a distance away from the hand-held unit and an optical subsystem that captures returned scattered radiation from said surface as a result of said light beam;

b. a wearable unit comprising a spectrograph that generates spectral data from the returned scattered radiation; and

c. a cable that connects said hand-held unit to said wearable unit, wherein said cable comprises one or more optical fibers that transports said returned scattered radiation collected by said optical subsystem in said hand-held unit to said spectrograph in said wearable unit.

32. The apparatus of claim 31, wherein said wearable unit comprises a processor that analyzes said spectrum data using spectroscopy techniques to identify a substance on said surface.

33. The apparatus of claim 32, and further comprising a display device in said wearable unit that is connected to said processor to display information for a substance determined to be present on said surface.