### ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

## 2pAO13. Three-dimensional ultrasonic imaging of temperature distributions.

**V. I. Mirgorodsky
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V. V. Gerasimov
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S. V. Peshin
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*Inst. of Radioeng. and Electron. of RAS, Fryazino, 141120 Moscow Region,
Russia
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The investigation of the new opportunity of an acoustothermometer's space
resolution realization is described. The method is based on the correlation
processing of signals received by the multi-element piezotransducer. It is
convenient to illustrate the method by the example of a reception of the
signals irradiated by a point noise source by means of the two spaced
transducers. The mutual correlation function of these signals has a maximum at
the delay that is proportional to the path's difference between the signal's
source and piezotransducers. Space resolution that is determined by the
correlation maximum's width is about a coherence length of the received
signals. At the easily achieved frequency band of the received signals (~1 MHz)
it may be of a relatively small value (~0.1 cm). The analytical solution of the
problem of space distribution of noncoherent radiation's sources by use of
correlation processing of signals received by various elements of the
transducers is presented. The opportunity of realization of a space resolution
less than 1 cm at a distance of about 7 cm is shown by the computer simulation.
It is essentially better using a known method based on the frequency's
analysis. Results of preliminary experiments are presented.