Remote, noninvasive, cardio-vascular activity tracer and hard target evaluator

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  • Publication Date:
    September 14, 2021
  • Additional Information
    • Patent Number:
      11119,072
    • Appl. No:
      16/536467
    • Application Filed:
      August 09, 2019
    • Abstract:
      A system for monitoring vibrations in a target region of interest may include a pulsed laser transmitter assembly, interferometric, telescope, and receiver optics, a photo-EMF detector assembly, signal conditioning/processing electronics, and a monitoring circuit/display. The detector assembly, which has a photo-EMF detector and amplifier circuits, generates an output signal indicative of the vibrations. A laser module outputs a source beam at a PRF of at least 2 Hz. A beam splitter device splits the source beam into separate interrogating and reference beams. The mirror directs the reference beam onto the photo-EMF detector for interference with a reflected return signal. The telescope optics generates an amplified return signal, and directs the amplified return signal to the photo-emf detector. The monitoring computer compares the output signal from the signal processor to a baseline to ascertain a difference therebetween, and generates a diagnostic signal indicative of the difference.
    • Inventors:
      UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA (Washington, DC, US)
    • Assignees:
      UNITED STATES OF AMERICA AS REPRESENTED BY THE ADMINISTRATOR OF NASA (Washington, DC, US)
    • Claim:
      1. A system for monitoring vibrations in a region of interest of a monitored target, the system comprising: a photo-EMF detector assembly having a photo-EMF detector and an amplifier circuit, and configured to generate an output signal indicative of the vibrations, wherein the photo-EMF detector assembly is a multi-pixel device constructed from Cadmium Telluride doped with a combination of transition metals; a laser assembly having: a laser generator configured to output a source beam; and a beam splitter device configured to split the source beam into an interrogating beam and a reference beam; a mirror angled with respect to the pulsed laser system to direct the reference beam onto the photo-EMF detector; telescope optics configured to amplify a return signal that is reflected from the region of interest to thereby generate an amplified return signal, and to direct the amplified return signal onto the photo-EMF detector to form interferometric fringes; and a monitoring circuit configured to receive the output signal from the photo-EMF detector, wherein the output signal is a current caused by motion of the interferometric fringes, compare the output signal to a baseline reference to ascertain a difference there between, and generate a diagnostic signal indicative of the difference; wherein the photo-EMF detector generates the output signal using information from the reference beam and the amplified return signal.
    • Claim:
      2. The system of claim 1 , wherein the laser assembly is a pulsed laser assembly and the source beam has a pulse repetition frequency of at least 2 Hz.
    • Claim:
      3. The system of claim 2 , wherein the laser generator is a pulsed microchip laser driven by non-linear optics.
    • Claim:
      4. The system of claim 1 , wherein the laser generator has a tunable wavelength and includes an optical parametric oscillator, an optical parametric generator, or a harmonic generator.
    • Claim:
      5. The system of claim 1 , wherein the laser generator includes a continuous wave laser with pseudo-random noise code.
    • Claim:
      6. The system of claim 1 , wherein the combination of transition metals includes Titanium and Chromium.
    • Claim:
      7. The system of claim 6 , wherein the Cadmium Telluride is further doped with Vanadium.
    • Claim:
      8. The system of claim 1 , wherein the pulse repetition frequency is at least 10 Hz.
    • Claim:
      9. The system of claim 2 , wherein the pulsed laser assembly includes an optical scanner located in a path of the source beam, and having an optical scan rate of at least about 2 KHz.
    • Claim:
      10. The system of claim 9 , wherein the optical scanner is one of a mechanical, electro-optical, acousto-optical, liquid crystal, or thin film-based optical scanner.
    • Claim:
      11. The system of claim 1 , further comprising an optical fiber connecting the telescope optics to the photo-EMF detector, wherein the optical fiber is configured to guide the amplified return signal toward the photo-EMF detector.
    • Claim:
      12. The system of claim 1 , wherein the monitored target is a human patient and the region of interest is an area of clothing of the patient.
    • Claim:
      13. The system of claim 1 , wherein the monitored target is a non-biological target, and the region of interest is a surface of the non-biological target.
    • Claim:
      14. A method for monitoring vibrations in a region of interest of a monitored target, the method comprising: generating a source beam at a pulse repetition frequency of at least about 10 Hz using a laser generator of a pulsed laser assembly; using a beam splitter device to split the source beam into an interrogating beam and a reference beam, wherein the interrogating beam is directed at the region of interest; directing the reference beam toward a photo-EMF detector using a mirror angled with respect to the pulsed laser system; optically amplifying a return signal from the region of interest using telescope optics to thereby generate an amplified return signal; directing the amplified return signal onto the photo-EMF detector to form interferometric fringes; and generating, via the photo-EMF detector using information from the reference beam and the amplified return signal, an output signal indicative of the vibrations using the photo-EMF detector and an amplifier circuit, wherein the output signal is a current caused by motion of the interferometric fringes; receiving the output signal from the photo-EMF detector via a monitoring circuit; comparing the output signal to a baseline reference, via the monitoring circuit, to thereby ascertain a difference therebetween; and generating a diagnostic signal indicative of the difference.
    • Claim:
      15. The method of claim 14 , wherein generating the source beam includes using (i) a pulsed microchip laser driven by non-linear optics, or (ii) a continuous wave laser with pseudo-random noise code.
    • Claim:
      16. The method of claim 14 , wherein the photo-EMF detector assembly is constructed from Cadmium Telluride doped with Titanium and Chromium.
    • Claim:
      17. The method of claim 14 , further comprising using an optical scanner located in a path of the source laser to scan the region of interest.
    • Claim:
      18. The method of claim 14 , further comprising using an optical fiber to guide the amplified return signal toward the photo-EMF detector, and wherein the monitored target is a human patient and the region of interest is an area of clothing of the patient.
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    • Other References:
      Wang et al., “A New Kind of Laser Microphone for Photoacoustic Applications”, Proceedings of the Army Science Conference (26th) Held in Orlando, Florida on Dec. 1-4, 2008. cited by applicant
      Wang et al., “Non-Contact Cardiac Activity Monitoring using Pulsed Laser Vibrometer”, Sensors & Transducers, vol. 162, Issue 1, Jan. 2014, pp. 173-176. cited by applicant
      Wang et al., “Biological Life Signs Detection Using High Sensitivity Pulsed Laser Vibrometer”, Conference on Lasers and Electro-Optics/Quantum Electronics and Laser Science Conference and Photonic Applications Systems Technologies, OSA Technical Digest Series (CD), Optical Society of America, 2007, paper CWK5. cited by applicant
      Wang et al., “Human Life Signs Detection Using High-Sensitivity Pulsed Laser Vibrometer”, IEEE Sensors Journal, vol. 7, No. 9, Sep. 2007. cited by applicant
    • Primary Examiner:
      Lee, Hwa Andrew
    • Attorney, Agent or Firm:
      Gorman, Shawn P.
      Soike, Jonathan B.
      Galus, Helen M.
    • Accession Number:
      edspgr.11119072