Adaptive inverse filtering with chirp for medical ultrasound

Abstract

In medical ultrasound imaging, the axial resolution is limited by the bandwidth of the transducer. In a linear frequency modulation (chirp) pulse coding technique for imaging, it is possible to inverse modulate the chirp amplitude by a function adaptively derived from the transducer frequency response. The transducer output then becomes an equalized chirp with a wider effective bandwidth. Subsequent pulse compression processing consequently improves the resolution. This concept has been evaluated experimentally in this paper.