Iterative inverse extrapolation for transducer characterization

Minimising cross-talk in medical ultrasound transducer arrays requires accurate knowledge of the transducer surface vibration. Direct measurement of this vibration is complicated. Therefore, in this work the transducer surface velocity distribution is reconstructed from pressure measurements using a conjugate gradient inversion scheme operating on the spatial component only. Numerical experiments show that this approach decreases the spatial smoothing introduced by other methods. The method is tested on transducers operating in the MHz-range and with elements having spatial dimensions in the order of 200 μm. Actual measurements show improved localisation of vibrational energy.