System, device, and method for detecting perturbations

• US 7,196,317 B1
• Filed: 03/25/2005
• Issued: 03/27/2007
• Est. Priority Date: 03/25/2005
• Status: Expired due to Fees

• Current Assignee: Virginia Tech Intellectual Properties, Inc.
• Original Assignee: Virginia Tech Intellectual Properties, Inc.
• Inventors: Spillman, William B. Jr., Meissner, Kenith II
• Primary Examiner(s): Luu; Thanh X.
• Application Number:
  US11/090,898
• Time in Patent Office: 732 Days
• Field of Search: 250/227.14, 250/227.15, 250/227.19, 385/13, 356/73.1
• US Class Current: 250/227.14
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/1102 Ballistocardiography
• CPC Class Codes: A61B 5/1115 Monitoring leaving of a patient support, e.g. a bed or a wheelchair
• CPC Class Codes: A61B 5/113 occurring during breathing
• CPC Class Codes: A61B 5/447 specially adapted for aiding the prevention of ulcer or pressure sore development, i.e. before the ulcer or sore has developed
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G01J 1/0219 Electrical interface; User interface
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0425 using optical fibers
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/4228 arrangements with two or more detectors, e.g. for sensitivity compensation

Abstract

Certain exemplary embodiments comprise a system comprising a spatially distributed multimode optical fiber; a pixelated photodetector configured to detect a plurality of optical signals provided from said fiber, a first portion of the optical signals indicative of modal conversion and a second portion of the optical signals indicative of modal interference, a predetermined area of said pixelated photodetector adapted to be illuminated by the first portion of the optical signals; and a signal processing module adapted to decode and interpret a plurality of detected variables related to the optical signals.

Claims

1. A system, comprising:

a spatially distributed multimode optical fiber;

a pixelated photodetector configured to detect a plurality of optical signals provided from said fiber, the optical signals related to perturbations applied to said optical fiber, a first portion of the optical signals indicative of modal conversion and a second portion of the optical signals indicative of modal interference, a predetermined central area of said pixelated photodetector adapted to be illuminated only by the first portion of the optical signals; and

a signal processing module adapted to decode and interpret a plurality of detected variables related to the optical signals.

2. The system of claim 1, further comprising a coherent optical source optically couplable to said optical fiber.

3. The system of claim 1, further comprising a laser diode optically couplable to said optical fiber.

4. The system of claim 1, further comprising a laser light pointer optically couplable to said fiber.

5. The system of claim 1, further comprising an electronic driver adapted to control light provided to said fiber.

6. The system of claim 1, wherein said fiber is integrating.

7. The system of claim 1, wherein said fiber is spatially distributed with respect to a patient bed for optimized detection of patient movement.

8. The system of claim 1, wherein said fiber is spatially distributed with respect to a patient bed for optimized detection of patient respiration.

9. The system of claim 1, wherein said fiber is spatially distributed with respect to a patient bed for optimized detection of patient heart rate.

10. The system of claim 1, wherein said fiber is spatially distributed with respect to a patient bed for optimized detection of any combination of patient movement, respiration rate, and heart rate.

11. The system of claim 1, wherein said fiber is adapted to provide modal conversion.

12. The system of claim 1, wherein said fiber is adapted to provide inter-modal interference.

13. The system of claim 1, wherein the optical signals comprise a speckle pattern.

14. The system of claim 1, further comprising a matched spatial filter adapted to spatially filter light provided to said fiber.

15. The system of claim 1, further comprising a matched spatial filter adapted to filter the optical signals.

16. The system of claim 1, further comprising a matched spatial filter adapted to spatially filter the plurality of detected variables of the optical signals.

17. The system of claim 1, further comprising a matched spatial filter adapted to filter a plurality of digitized images provided by said photodetector.

18. The system of claim 1, wherein said photodetector is optically couplable to said optical fiber.

19. The system of claim 1, wherein said photodetector provides an output proportional an integrated perturbation along said fiber.

20. The system of claim 1, further comprising a wireless digital module coupled to said photodetector and adapted to wirelessly transmit a wireless signal encoding the plurality of detected variables of the optical signals.

21. The system of claim 1, further comprising a wireless digital module coupled to said photodetector and adapted to wirelessly transmit a wireless signal encoding a plurality of digitized images of the optical signals.

22. The system of claim 1, further comprising a wireless receiver adapted to receive a wireless signal encoding the plurality of detected variables of the optical signals.

23. The system of claim 1, further comprising a wireless receiver adapted to receive a wireless signal encoding the plurality of detected variables of the optical signals, said wireless receiver coupled to said signal processing module.

24. The system of claim 1, wherein said signal processing module is adapted to decode a plurality of digitized images and to interpret one or more variables of the plurality of digitized images, the plurality of digitized images related to the optical signals.

25. The system of claim 1, wherein said signal processing module is adapted to provide an output proportional to an absolute value of Δ

P/Δ

t, where P is an integrated perturbation along said optical fiber and t is time.

26. The system of claim 1, wherein said signal processing module is adapted to provide matched spatial filtering of a plurality of digitized images to optimize a signal-to-noise ratio, the plurality of digitized images related to the optical signals.

27. The system of claim 1, wherein said signal processing module is adapted to process a predetermined portion of the optical signals.

28. The system of claim 1, wherein said signal processing module is adapted to process a portion of the optical signals, the portion associated with a human vital sign.

29. The system of claim 1, wherein said signal processing module is adapted to interpret a frequency of a perturbation of the fiber.

30. The system of claim 1, wherein said signal processing module is adapted to interpret a frequency of a perturbation of the plurality of detected variables.

31. The system of claim 1, wherein said signal processing module is adapted to interpret fluctuations in a speckle pattern of the optical signals.

32. The system of claim 1, wherein said signal processing module is adapted to interpret a portion of the plurality of detected variables associated with the first portion of the optical signals.

33. The system of claim 1, wherein said signal processing module is adapted to interpret a portion of the plurality of detected variables associated with the second portion of the optical signals.

34. The system of claim 1, wherein said signal processing module is adapted to interpret a frequency of at least a portion of the perturbations, the interpreted frequency corresponding to a patient vital sign.

35. The system of claim 1, wherein said signal processing module is adapted to interpret a frequency of at least a portion of the perturbations, the interpreted frequency corresponding to a patient movement.

36. The system of claim 1, wherein said signal processing module is adapted to monitor the plurality of detected variables for a change in a patient'"'"'s vital sign.

37. The system of claim 1, wherein said signal processing module is adapted to monitor the plurality of detected variables for a change in a patient'"'"'s movement.

38. The system of claim 1, wherein said signal processing module is adapted to automatically monitor the plurality of detected variables for a change in patient movement, respiration rate, or pulse rate.

39. The system of claim 1, wherein said system comprises an STM sensor and a HOME sensor.

40. A method, comprising:

transmitting from a wireless digital pixelated photodetector coupled to a spatially distributed multimode optical fiber a signal encoding a plurality of detected variables of optical signals emerging from the optical fiber, a first portion of the optical signals related to a first plurality of perturbations applied to the optical fiber, indicative of modal conversion, and illuminating only a predetermined central area of the photodetector, and a second portion of the optical signals related to a second plurality of perturbations applied to the optical fiber, indicative of modal interference, and illuminating other than the predetermined central area of the photodetector;

receiving the signal at a wireless receiver;

decoding the signal at a signal processing module coupled to the wireless receiver; and

interpreting the plurality of detected variables of the decoded signal.

41. A method, comprising:

spatially distributing a multimode optical fiber in a predetermined pattern for facilitating sensing of a predetermined type of perturbation;

transmitting optical signals from the spatially distributed integrating multimode optical fiber;

detecting the optical signals at a pixelated photodetector, the optical signals related to perturbations applied to the optical fiber, a first portion of the optical signals indicative of modal conversion and a second portion of the optical signals indicative of modal interference, a predetermined central area of said pixelated photodetector adapted to be illuminated only by the first portion of the optical signals; and

transmitting a wireless signal encoding a plurality of detected variables of the optical signals.

42. A machine-readable medium comprising instructions for activities comprising:

decoding a wireless signal obtained from a wireless digital pixelated photodetector coupled to an optical fiber spatially distributed in a predetermined pattern for facilitating sensing of a predetermined type of perturbation, the wireless signal encoding a plurality of detected variables of optical signals emerging from the spatially distributed optical fiber, a first portion of the optical signals related to a first plurality of perturbations applied to the optical fiber, indicative of modal conversion, and illuminating only a predetermined central area of the photodetector, and a second portion of the optical signals related to a second plurality of perturbations applied to the optical fiber, indicative of modal interference, and illuminating other than the predetermined central area of the photodetector; and

interpreting the plurality of detected variables of the decoded signal.