【作者】 刘民；

【导师】 周激流；

【作者基本信息】 四川大学 ， 通信与信息系统， 2006， 硕士

【摘要】 随着电子学、计算机技术、材料学等相关领域技术的飞速发展，医学影像技术得到了空前的发展。作为医学影像技术的一个分支，超声成像与其它医学成像方法相比，具有对人体无损害、便宜、便捷、能够实时显示器官或组织运动情况等特点，在临床上获得了非常广泛的应用。 由于临床医生对于超声成像仪器的功能和性能的要求不断提高，使得超声成像仪器需要增加越来越多的功能。新的成像功能往往需要大量的数值，而由于超声成像有实时性的要求，这也就意味着不能耗费太多的时间来进行大量的计算，从而才能保证超声系统的帧率不会太低，影响其实时性。B模式成像作为超声成像仪器的基本成像模式，是很多成像模式的基础，如果能够缩短B模式的成像时间，那么可以为后续大计算量的功能模块提供更多的时间余量。B模式超声成像的回波信号处理部分，涉及大量的卷积运算，如果能够将卷积的运算量有效地减少，对于B模式超声成像的速度是会有很大的提高的。 近年来，信号处理领域的多速率信号处理技术发展非常迅速。多速率信号处理技术可以有效的减少系统的工作量。理论证明多速率信号处理技术实现的多级窄带滤波器结构可以有效地减少卷积所做的乘法运算量。我们知道为了获得一个过渡带很窄的滤波器，就需要一个相应比较长的滤波器来滤波。而多级滤波器的性能可以和使用单级长滤波器的滤波的性能相当，可以替代单级滤波器来做快速计算。 基于以上知识，本文将多速率信号处理技术用于B模式超声成像的回波信号处理部分，用两级多速率抽取滤波器结构来替代传统的单级抽取滤波器，用更多还原

【Abstract】 As the rapid development of electronic engineering, computer technique, materials science, and other involved area. Medical imaging techniques have been unprecedented developed. As a branch of medical imaging techniques, ultrasound imaging has been widely applied in clinic diagnosis because of its non-invasiveness, low price, convenience and real-time visualization of human organ and tissue motion.Present now clinician calls for a new ultrasound diagnostic apparatus with more and more diagnostic functions and better quality. As new imaging function always need a mass of mathematical computing, which cannot meet the requirement of real-time imaging. That is to say an ultrasound diagnostic apparatus cannot spend too much time on sophisticated computing to ensure least frame rate needed for real-time imaging. B-mode imaging, as a basic imaging mode of an ultrasound diagnostic apparatus, is the base of many other imaging mode. If B-mode imaging time can be reduced, subsequent processing will have more time for the corresponding processing. B-mode ultrasound echo signal processing needs a mass of convolution. If the time spend on convolution can be reduced, B-mode imaging will be accelerated greatly.Recently, Multi-rate signal processing of signal processing field has been developed rapidly. Multi-rate signal processing technique can effectively reduce system workload. Multi-rate signal processing theory shows multi-stage narrow band filter designed with Multi-rate signal processing theory can effectively reduce multiplication times needed for convolution. As we all know we need a long filter to have a sharp transition band. Multi-stage filter has the same performance with a long filter, which has much less filter coefficients. It can replace the single long filter to improve system speed.Based on the theory, this paper introduces Multi-rate signal processing technique in original B-mode ultrasound echo signal processing. Two-stage multi-rate decimation filter is used here to replace the original single stage decimation filter for DC cancellation and decimation filtering. Also we noticed that only used two-stage更多还原