Conference Paper

Optimal focusing through aberrating media: a comparison between time reversal mirror and time delay correction techniques

Lab. Ondes et Acoust., Paris Univ.
DOI: 10.1109/ULTSYM.1991.234304 In proceeding of: Ultrasonics Symposium, 1991. Proceedings., IEEE 1991
Source: IEEE Xplore

ABSTRACT The problem of focusing an ultrasonic beam through an
inhomogeneous medium was investigated experimentally for conventional
time delay focusing, adaptive time delay focusing, and time reversal
focusing. It is shown that neither time delay based technique gives a
properly focused beam for all aberrator locations. Only time reversal
focusing allows a robust focusing regardless of the aberrator location.
The matched filter theory of signal processing allows an interpretation
of this result: time reversal focusing provides the optimal input to the
linear system consisting of the acousto-electric and diffraction impulse

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