合成孔径序列波束形成轴向运动补偿方法  

An Axial Motion Compensation Method for Synthetic Aperture Sequential Beamforming

作　　者：孟晓辉[1] 理华[1] 王君琳[1] 

机构地区：[1]中国科学院声学研究所,北京100190

出　　处：《中国生物医学工程学报》2015年第5期558-565,共8页Chinese Journal of Biomedical Engineering

基　　金：国家自然科学基金(11204346);中国科学院声学研究所所长择优基金(Y454221341);中国科学院声学研究所创新前瞻项目(Y154211341)

摘　　要：合成孔径序列波束方法是一种新颖的医学超声成像方法,采用两个阶段的波束形成,在传统的超声成像系统中实现合成孔径成像,在不需要存储和传输大量射频回波数据的情况下,提高医学超声图像的分辨率。该方法的前提是假设成像目标静止不动,而通过仿真分析发现运动会造成成像目标位置错误。针对此问题,提出一种合成孔径序列波束形成运动估计和补偿方法:首先通过在同一位置连续发射接收两次以获取用于运动估计的数据,然后采用互相关方法对第一阶段波束形成得到的低分辨率图像进行运动估计和补偿,再对其做第二次波束形成得到高分辨率图像。Field II仿真结果显示,所提出的运动补偿方法可以得到正确的目标位置。对于运动速度为0.1 m/s的点目标,运动补偿后的平均横向分辨率与静止点目标相比仅降低2.03%,对比度降低2.7 d B。对于运动速度为0.2 m/s的囊目标,运动补偿后图像的对比度分辨率较静止情况仅降低8.53%,进一步说明所提出的运动补偿方法有效。Synthetic aperture sequential beamforming（ SASB） is a two-stage beamforming procedure,which can be applied to B-mode imaging with an implementation of low complexity compared to the traditional synthetic transmit aperture（ STA） imaging. However,like the STA imaging,the SASB is susceptible to motion artifacts due to the summation of a number of RF-data created at different time instances. In this paper,a tissue motion estimation and compensation method was proposed. First,the inter-firing motion was estimated by crosscorrelating with extra firings. At last,the second stage beamformer created a set of high resolution image points by combining information from multiple first stage focused scan lines. Field II simulation results showed that the motion compensation method proposed in this paper exhibited enhanced ability to correct location of moving tissue. When the points were moving at 0. 1 m / s,the average lateral resolution after motion compensation was only reduced by 2. 03% comparing to the static case,and contrast reduction was 2. 7 d B. Moreover,when cysts were moving at 0. 2 m / s,the contrast resolution of image after motion compensation was only reduced by8. 53% comparing to the static case.

关 键 词：合成孔径 合成孔径序列波束形成 运动补偿 

分 类 号：R445.1[医药卫生—影像医学与核医学]