Stefan Rupitsch, Stefan Kindermann, Bernhard Zagar,
"Estimation of the Surface Normal Velocity of High Frequency Ultrasound Transducers"
, in IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency control, Vol. 55, Nummer 1, 1-2008
Estimation of the Surface Normal Velocity of High Frequency Ultrasound Transducers
Sprache des Titels:
This paper is concerned with the characterization
of the true locally resolved surface normal velocity
of an assumed piston-type ultrasonic transducer. Instead of
involving a very complicated direct pointwise measurement
of the velocity distribution, an inverse problem is solved
which yields a spatially discretized weighting vector for the surface normal velocity of the transducer. The study deals with a spherically focused high frequency transducer, which is driven in pulse-echo mode. As a means of posing the inverse problem, the active transducer surface is divided into
annuli of equal surface so that for each annulus the spatial
impulse response can be calculated. An acrylic glass
plate acts as a simple structured target. The resulting illposed nonlinear inverse problem is solved with an iterative regularized Gauss–Newton algorithm. The solution of the inverse problem yields an estimated weight for the surface normal velocity for each annulus. Experimental results for a thin copper wire target are compared to simulation results for both uniform and estimated surface normal velocities.
Sprache der Kurzfassung:
IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency control