Ultrasound Probe Bandwidth Enhancement Combined with Non-Stationary Compression Filters to Improve Image Quality

Resolution Enhancement Compression (REC)is a pulse compression technique that can provide significant improvements in terms of imaging quality over Classical Pulsed (CP)ultrasonic imaging techniques, by employing frequency and amplitude modulated transmitted signals. However, as it was shown in [1] and [2] the REC compression can be partially impaired by such propagation phenomena as tissue attenuation effect and probe's spatial impulse response. In our previous work [1], we showed how REC can be adapted to compensate for the tissue attenuation effect. Here, a technique that allows compensating the spatial impulse response on REC imaging is proposed (I-REC). The core principle of the method consists in spatially adapting the REC compression filters. Applied to conventional focused imaging, the I-REC performance was compared to the one of conventional REC (without spatial impulse response compensation)and CP. The experimental results show the importance of taking into account the spatial impulse response of the probe. Indeed, I-REC enhanced the axial resolution by 51 % compared to the conventional technique, against an enhancement of only 34% between REC and CP. The contrast-to-noise ratio was enhanced by 20% in comparison to REC, when I-REC was used.