Real-time base-band pulse compression imaging

In ultrasound imaging, pulse compression methods based on the transmission of “long” coded pulses can be used to improve the penetration depth while preserving good axial resolution. The performance of these algorithms is strongly affected by the frequency dependent attenuation causing severe mismatch of the receive filter. This, together with the involved additional computational load, has probably so far discouraged the implementation of pulse compression methods in real-time imaging systems. In this paper we report on a low-computational-cost real-time pulse compression system operating on beamformed, demodulated and down-sampled data. The system has been implemented on ULA-OP (MSDLab, Florence, Italy) without any hardware modification, by adapting the DSP real-time firmware and the software user-interface. Experimental tests show that the penetration depth is increased by more than 1.5 cm at 9 MHz transmission.