Data Acquisition for Scanning Tomographic Acoustic Microscopy

  • A. Meyyappan
  • G. Wade
Part of the Acoustical Imaging book series (ACIM, volume 16)

Abstract

Acoustic microscopes are valuable in non-destructive evaluation because of their ability to provide high-resolution images of microscopic structure in small objects. When such a microscope operates in the transmission mode, the micrographs are simply two-dimensional shadowgraphs of three-dimensional objects and the resultant images are frequently difficult to comprehend because of diffraction and overlapping. This is especially true in the case of objects of substantial thickness with complex structures. We have developed a scanning tomographic acoustic microscope (STAM) to overcome these problems.

We have proposed two different rotation schemes to obtain projections for reconstructing the tomograms. The first involves rotating the transducer and the second, rotating the object. To avoid phase errors, the distance between the centers of the transducer and the object should be kept constant, or at least accurately known, throughout the rotations.

In this paper, we examine the stringent geometrical requirement for these schemes. We show, by computer simulation, that small misplacements of the order of a fraction of a wavelength are capable of destroying the image. We therefore propose a third approach which eliminates this problem since it does not require rotating or moving either the transducer or the object.

Keywords

Attenuation Acoustics 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Z. C. Lin, H. Lee, and G. Wade, Scanning tomographic acoustic microscope: a review, IEEE Trans. Sonics Ultrason. SU-32: 168 (1985).Google Scholar
  2. 2.
    Z. C. Lin, H. Lee, and G. Wade, Back-and-forth propagation for diffraction tomography. IEEE Trans. Sonics Ultrason. SU-31: 626 (1984).ADSGoogle Scholar
  3. 3.
    G. Wade, and A. Meyyappan, Scanning tomographic acoustic microscopy: princi-ples and recent developments, in SPIE Proceedings 768 (1987) (accepted for publication).Google Scholar
  4. 4.
    Z. C. Lin, H. Lee, and G. Wade, M. G. Oravecz, and L. W. Kessler, Holographic image reconstruction in scanning laser acoustic microscopy, IEEE Trans. Ultrason. Ferroelec. Frequency Cont. UFFC-34: 293 (1987).ADSGoogle Scholar
  5. 5.
    H. Lee, and C. Ricci, Modification of the scanning laser acoustic microscope for holographic and tomographic imaging, Appl. Phys. Lett. 49:1336 (1986).ADSCrossRefGoogle Scholar
  6. 6.
    Z. C. Lin, H. Lee, and G. Wade, M. G. Oravecz, and L. W. Kessler, Data acquisition in tomographic acoustic microscopy, in Proc. IEEE Ultrason. Symp., Atlanta (1983).Google Scholar
  7. 7.
    H. Lee, C. F. Schueler, G. Flesher, and G. Wade, Ultrasound planar scanned tomography, in “Acoustical Imaging,” vol. 11, J. Powers, ed., Plenum, New York (1982).Google Scholar
  8. 8.
    R. L. Rylander, “A laser scanned ultrasonic microscope incorporating a time- delay interferometric detector,” Ph.D. dissertation, University of Minnesota, Minneapolis (1982).Google Scholar

Copyright information

© Plenum Press, New York 1988

Authors and Affiliations

  • A. Meyyappan
    • 1
  • G. Wade
    • 1
  1. 1.Department of Electrical and Computer EngineeringUniversity of CaliforniaSanta BarbaraUSA

Personalised recommendations