摘要
为了提高超声回波信号的信噪比和空间分辨率,获取血流速度剖面,使用编码激励技术来改进传统的医学超声血流测量系统。提出一种具有"零相关窗"的互补码序列,该序列具有局部最佳非周期自相关性,可以在特定区域内完全消除旁瓣,并且采用易于硬件实现的二相编码序列。介绍了该序列的构造方法和特性,并分析了用其测量血流速度剖面的原理和方法。采用自主开发研制的激励超声测量硬件平台,通过单反射面回波实验,证实了该序列比单脉冲和13位Barker码序列具有更优良的信噪比增益。通过搭建模拟人体血流测量实验装置进行仿血流的速度剖面测量试验。实验结果表明,该序列激励超声信号同时具有优良的空间分辨率,在发射换能器的中心频率为5 MHz时,可达到0.3 mm的纵向分辨率,取得了良好的测量效果。
This study is purposed to acquire blood velocity profiles.Usually coded excitation is applied to improve signal-to-noise ratio and space resolution of the ultrasonic echo signals.In this work,a zero correlation window complementary coded sequence was presented.The sequence had prefect local autocorrelation and no sidelobes in the window.In addition,as a binary phase coded sequence,it was convenient to generate by hardware.The sequence construction and its features were introduced as well as the principle of measuring blood velocity profile.An ultrasonic measurement platform using coded excitation was setup to conduct mirror reflection experiment.It is proved that the sequence provided higher SNR gain than pulse and 13-bit Barker code sequence.Then the velocity profile of blood was measured using a flow circulation device.The results showed that the longitudinal resolution could reached 0.3mm when the center frequency of the transducer was 5 MHz.
出处
《中国生物医学工程学报》
CAS
CSCD
北大核心
2010年第4期538-544,共7页
Chinese Journal of Biomedical Engineering
基金
上海市重点学科建设资助项目(B112)
关键词
编码激励
零相关窗互补码
血流速度剖面
实验研究
coded excitation
zero correlation window complementary code
blood velocity profile
experimental study
