NEURAL NETWORK DEMODULATION FOR AN OPTICAL SENSOR

• US 20070297714A1
• Filed: 06/12/2007
• Published: 12/27/2007
• Est. Priority Date: 06/12/2006
• Status: Active Grant

• Current Assignee: Curators of the University of Missouri (University of Missouri)
• Original Assignee: Curators of the University of Missouri (University of Missouri)
• Inventors: Dua, Rohit, Wunsch, Donald, Watkins, Steve
• Granted Patent: US 7,603,004 B2
• Time in Patent Office: Days
• US Class Current: 385/14
• CPC Class Codes: G01L 1/24 by measuring variations of optical properties of material when it is stressed, e.g. by photoelastic stress analysis using infrared, visible light, ultraviolet
• CPC Class Codes: G01M 11/08 Testing mechanical properties G01M11/005 takes precedence
• CPC Class Codes: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0091 by using electromagnetic excitation or detection

Abstract

Methods and systems of neural network demodulation for an optical sensor. An optical sensor may be coupled to a structure and be capable of reflecting a reflected optical signal. A wavelength of the reflected optical signal may be spread based on a strain being applied to the structure. A replication device may receive the reflected optical signal from the optical sensor and produce a plurality of optical signals. A filter may be coupled to the replication device to receive an optical signal from the plurality of optical signals and filter the received optical signal. A detector may receive the filtered optical signal and provide a voltage output proportional to an amount of the filtered optical signal received. A neural network may receive the voltage output and determine the strain on the structure.

Claims

1. A system comprising:

an optical sensor coupled to a structure, the optical sensor to receive a source optical signal and reflect a reflected optical signal, at least one wavelength of the reflected optical signal being spread based on a strain being applied to the structure;

a replication device coupled to the optical sensor, the replication device to receive the reflected optical signal from the optical sensor and produce a plurality of optical signals;

at least one filter coupled to the replication device to receive an optical signal from the plurality of optical signals and filter the received optical signal;

at least one detector, coupled to the at least one filter, to receive the filtered optical signal and provide an output signal representing an amount of the filtered optical signal received; and

a neural network coupled to the at least one detector, the neural network to receive the output signal from the at least one detector and determine the strain on the structure.

2. The system of claim 1, further comprising:

an analysis subsystem to receive a further signal from the neural network for further processing and analysis.

3. The system of claim 1, wherein the structure is selected from a group of structures consisting of an automotive structure, an aircraft structure, and a civil engineering structure.

4. The system of claim 1, wherein the optical sensor includes at least one of a fiber optical sensor or Bragg optical grating sensor.

5. The system of claim 1, wherein the replication device is coupled to the optical sensor with a communication connection, the communication connection comprising at least one of a fiber, a cable, a wire, or an optical transmission medium.

6. The system of claim 1, wherein the replication device is selected from a group of replication devices consisting of a splitter or an expander.

7. The system of claim 1, wherein the at least one detector includes at least one photodetector.

8. The system of claim 1, wherein a number of filters of the at least one filter is equal to a number of detectors of the at least one detector.

9. The system of claim 1, wherein a number of filters of the at least one filter is one less than a number of detectors of the at least one detector.

10. The system of claim 1, wherein the neural network has characteristics of the at least one filter and uses the characteristics when determining the strain on the structure.

11. The system of claim 1, wherein the output signal is a voltage output promotional to an amount of the filtered optical signal received.

12. A method comprising:

receiving a reflected optical signal from an optical sensor, the optical sensor coupled to a structure, at least one wavelength of the reflected optical signal being spread based on a strain being applied to the structure;

replicating the reflected optical signal to produce a plurality of optical signals;

filtering at least one of the plurality of optical signals to produce at least one filtered optical signal;

detecting the at least one filtered optical signal to determine an output signal representing an amount of the filtered optical signal received; and

performing a neural network analysis on the output signal to determine an amount of strain applied to the structure.

13. The method of claim 12, wherein detecting further comprises:

detecting an unfiltered optical signal from the plurality of optical signals to determine the voltage output proportional to an amount of the unfiltered optical signal.

14. The method of claim 12, wherein performing the neural network analysis comprises:

preprocessing the output signal; and

performing the neural network analysis on the preprocessed output to determine the amount of strain applied to the structure.

15. The method of claim 14, wherein preprocessing the output signal comprises at least one of scaling the output signal or normalizing the output signal.

16. The method of claim 12, wherein performing the neural network analysis comprises:

receiving an additional signal from an additional sensor; and

performing the neural network analysis on the output signal using the additional signal to determine the amount of strain applied to the structure.

17. The method of claim 16, wherein the additional sensor is selected from a group of sensors consisting of a temperature sensor, a time and date sensor, or an environmental factor sensor.

18. The method of claim 12, wherein the at least one wavelength of the reflected optical signal being spread based on the strain is a center wavelength with a linear shift.

19. The method of claim 12, further comprising:

producing a classification of the strain.

20. A method comprising:

receiving a reflected optical signal from an optical sensor, the optical sensor coupled to a structure, at least one wavelength of the reflected optical signal being spread based on a strain being applied to the structure;

decomposing the reflected optical signal to produce a plurality of different components of the reflected optical signal;

filtering the plurality of different components to produce a plurality of filtered components;

detecting the plurality of filtered components to determine an output signal representing an amount of at least one of the plurality of filtered components; and

performing a neural network analysis on the output signal to determine an amount of strain applied to the structure.

21. The method of claim 20, further comprising:

performing further processing and analysis on the amount of strain applied to the structure.

22. The method of claim 20, wherein the at least one wavelength of the reflected optical signal being spread based on the strain is a center wavelength with a linear shift.