基于线性调频信号的高帧率超声成像系统的改进

Improvement on High Frame Rate Ultrasonic Imaging System Based on Linear Frequency-modulated Signal

线性调频信号用于高帧率超声成像系统能实现快速成像,并能显著提高成像系统的信噪比,但回波信号通过匹配滤波器后,输出压缩脉冲的旁瓣会引起较小目标的丢失。我们对基于线性调频信号的高帧率超声成像系统进行改进。采用预失真的线性调频信号作为激励信号,在接收端对接收信号通过失配滤波器处理。结果表明基于线性调频信号的高帧率超声成像系统经过改进之后,在提高系统信噪比的同时也能提高轴向分辨率。

The high frame rate （HFR） ultrasonic imaging system based on linear frequency-modulated （LFM） signal constructs images at a high frame rate; the signal-to-noise ratio （SNR） of this system can also be improved. Unfortunately, such pulse compression methods that increase the SNR usually cause range sidelobe artifacts. In an imaging situation, the effects of the sidelobes extending on either side of the compressed pulse will be self-noise along the axial direction and masking of weaker echoes. The improvement on high frame rate ultrasonic imaging system based on LFM signal is considered in this paper. In this proposed scheme, a predistorted LFM signal is used as excited signal and a mismatched filter is applied on receiving end. The results show that the proposed HFR ultrasonic imaging system can achieve higher SNR and the axial resolution is also improved.