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An Enhanced Sharpness on Acoustic Focus Via Artificial Iterative Phase Conjugation Processing

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Abstract

For a low-frequency source in a homogenous medium, when the source is focused by phase conjugation (also referred to as the time reversal in the time domain), the focal spot is large because of the half-wavelength limit. In this paper, to reduce the focal spot size, artificial iterative phase-conjugated processing is proposed based on passive phase conjugation to focus a point-like source. As AIPCP operates in iteration mode using a computer, the iteration loops of each transducer are calculated independently, and then, AIPCP is achieved by summing the iteration outputs of all transducers together. Numerical simulations and experiments on an audible sound field are employed to illustrate that AIPCP generates a narrower focal spot than passive phase conjugation. Further analyses considered the theoretical change in focal spot size with the iteration number using Fraunhofer far-field approximation, and the result shows that the focal spot size decreases with increase in the iteration number. This finding is predicted in the near field and validated in the far field by simulations and experiments. Moreover, the half-wavelength limit is overcome at a distance from the sound source equal to the wavelength.

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References

  1. Fink M., Prada C., Wu, F., et al.: Self focusing in inhomogeneous media with time reversal acoustic mirrors. In: Ultrasonics Symposium 1989 Proceedings IEEE, vol. 2, pp. 681–686 (1989)

    Google Scholar 

  2. Jackson, D.R., Dowling, D.R.: Phase conjugation in underwater acoustics. J. Acoust. Soc. Am. 89(1), 171–181 (1991)

    Article  Google Scholar 

  3. Fink, M.: Time-reversal of ultrasonic fields, 1. Basic principles. IEEE Trans Ultrason Ferroelectr. Freq. Control 39(5), 555–566 (1992)

    Article  Google Scholar 

  4. Fink, M.: Time reversed acoustics. Phys. Today 50(3), 34–40 (1997)

    Article  MathSciNet  Google Scholar 

  5. Zang, R., Wang, B.-Z., Ding, S., et al.: Time reversal multi-target imaging technique based on eliminating the diffusion of the time reversal field. Acta Phys. Sin. 65(20), 204102-1–204102-6 (2016)

    Google Scholar 

  6. Ciuonzo, D.: On time-reversal imaging by statistical testing. IEEE Signal Proc Lett. 24(7), 1024–1028 (2017)

    Article  Google Scholar 

  7. Dowling, D.R.: Phase-conjugate array focusing in a moving medium. J. Acoust. Soc. Am. 94(3), 1716–1718 (1993)

    Article  Google Scholar 

  8. Ciuonzo, D., Rossi, P.S.: Noncolocated time-reversal music: high-SNR distribution of null spectrum. IEEE Signal Proc Lett. 24(4), 397–401 (2017)

    Article  Google Scholar 

  9. Du, Q., Song, Y., Mu, T., et al.: High-resolution imaging utilizing space-frequency DORT combining the extrapolated virtual array. J. Microw. Optoelectron. Electromagn. Appl. 16(3), 756–764 (2017)

    Article  Google Scholar 

  10. Harazi, M., Yang, Y., Fink, M., et al.: Time reversal of ultrasound in granular media. Eur. Phys. J. Spec. Top. 226(7), 1487–1497 (2017)

    Article  Google Scholar 

  11. Fannjiang, A.C.: On time reversal mirrors. Inverse Probl. 25(9), 095010 (2009)

    Article  MathSciNet  MATH  Google Scholar 

  12. de Rosny, J., Fink, M.: Focusing properties of near-field time reversal. Phys. Rev. A. 76(6), 065801 (2007)

    Article  Google Scholar 

  13. Fink, M.: Time-reversal waves and super resolution. J. Phys: Conf. Ser. 124, 012004 (2008)

    Google Scholar 

  14. Lerosey, G., De Rosny, J., Tourin, A., et al.: Focusing beyond the diffraction limit with far-field time reversal. Science 315, 1120–1122 (2007)

    Article  Google Scholar 

  15. Blomgren, P., Papanicolaou, G., Zhao, H.K.: Super-resolution in time-reversal acoustics. J. Acoust. Soc. Am. 111(1), 230–248 (2002)

    Article  Google Scholar 

  16. Bavu, E., Berry, A.: High-resolution imaging of sound sources in free field using a numerical time-reversal sink. Acta Acust. United Acust. 95(4), 595–606 (2009)

    Article  Google Scholar 

  17. Heedong, C., Ogawa, Y., Nishimura, T., et al.: Iterative angle-and-time-domain gating technique for time-reversal music imaging. Signal Process. 111, 39–49 (2015)

    Article  Google Scholar 

  18. Garnier, J., Fink, M.: Super-resolution in time-reversal focusing on a moving source. Wave Motion 53, 80–93 (2015)

    Article  MathSciNet  Google Scholar 

  19. Ma, H., Zeng, X., Wang, H.: A novel dual-channel matching method based on time reversal and its performance for sound source localization in enclosed space. Acoust. Aust. 44(3), 417–428 (2016)

    Article  Google Scholar 

  20. de Rosny, J., Fink, M.: Overcoming the diffraction limit in wave physics using a time-reversal mirror and a novel acoustic sink. Phys. Rev. Lett. 89(12), 124301 (2002)

    Article  Google Scholar 

  21. Bi, C.-X., Li, Y.-C., Zhang, Y.-B., et al.: Super-resolution imaging of low-frequency sound sources using a corrected monopole time reversal method. J. Sound Vib. 410, 303–317 (2017)

    Article  Google Scholar 

  22. Liu, S., Li, S., Zhao, D.: Identification of complex sound source by the phase conjugation method. J. Low Freq. Noise Vib. Act. Control 29(2), 91–100 (2010)

    Article  Google Scholar 

  23. Prada, C., Wu, F., Fink, M.: The iterative time-reversal mirror—a solution to self-focusing in the pulse echo mode. J. Acoust. Soc. Am. 90(2), 1119–1129 (1991)

    Article  Google Scholar 

  24. Dowling, D.R.: Acoustic pulse-compression using passive phase-conjugate processing. J. Acoust. Soc. Am. 95(3), 1450–1458 (1994)

    Article  Google Scholar 

  25. Jamshidi, A., Moezzi, S.: Experiential assessment of iteratively residual interference elimination in the passive phase conjugation for acoustic underwater communications. Ocean Eng. 105, 287–294 (2015)

    Article  Google Scholar 

  26. Hui, J., Ma, J., Li, F., et al.: Passive localization technology using time reversal with a two-sensor array. J. Harbin Eng. Univ. 28(11), 1247–1251 (2007)

    Google Scholar 

  27. Sheng, X., Zhou, W., Bao, X., et al.: Study on passive iterative time reversal mirror. Tech. Acoust. 27(4), 588–592 (2008)

    Google Scholar 

  28. Sheng, X., Luo, F., Guo, Y., et al.: Research on selective passive focusing technology based on dummy iterative time-reversal mirror. Acta Armamentarii 31(3), 322–326 (2010)

    Google Scholar 

  29. Song, H.C., Kuperman, W.A., Hodgkiss, W.S., et al.: Iterative time reversal in the ocean. J. Acoust. Soc. Am. 105(6), 3176–3184 (1999)

    Article  Google Scholar 

  30. Ikeda, O.: An image-reconstruction algorithm using phase conjugation for diffraction-limited imaging in an inhomogeneous-medium. J. Acoust. Soc. Am. 85(4), 1602–1606 (1989)

    Article  Google Scholar 

  31. Yang, F., Wang, H., Shen, X., et al.: Active time reversal detection performance of a single transducer in acoustic multipath channel. Tech. Acoust. 30(4), 359–363 (2011)

    Google Scholar 

  32. Pillai, S.U., Burrus, C.S.: Array signal processing. Springer, New York (1989)

    Book  Google Scholar 

  33. Zhang, Y., Bin, C., Chen, J., et al.: Separation method of multiple coherent sources based on hybrid holographic algoritm. Chin. J. Mech. Eng. 43(9), 173–178 (2007)

    Article  Google Scholar 

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Funding

We would like to gratefully acknowledge the support of the National Natural Science Foundation of China (Grant No. 51609037).

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Correspondence to Sheng Li.

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Li, T., Li, S. & Liu, S. An Enhanced Sharpness on Acoustic Focus Via Artificial Iterative Phase Conjugation Processing. Acoust Aust 46, 227–240 (2018). https://doi.org/10.1007/s40857-018-0138-7

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  • DOI: https://doi.org/10.1007/s40857-018-0138-7

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