北京生物医学工程

一种新的X-wave仿真方法

A novel algorithm of simulation based on X-wave

作者：李雅琴花少炎丁明跃尉迟明

单位：华中科技大学图像识别与人工智能研究所图像信息处理与智能控制教育部重点实验室(武汉430074)

分类号：

出版年·卷·期（页码）：2012·31·6（586-590）

摘要：

目的 X-wave作为一种典型的非衍射波，具有很强的潜在价值，在使用有限孔径传感器的情况下，能够在较深的场域内保持不发散的优点，比传统的超声系统节省了动态聚焦的计算过程，能有效提高超声成像的速度。但X-wave的理论激励信号比较复杂，导致其在仿真经济成本和时间耗费过高。基于此，本文提出一种使用矩形波或三角波的简单波取代复杂的激励信号的方法。方法首先使用简单波（矩形波和三角波）取代原有的X-wave的激励信号，采用L2的优化算法选择哪一种简单波最接近原有的激励信号，再通过计算空间脉冲响应实现声场的仿真。结果声场仿真结果显示，该方法能最大限度减少激励信号的差异，减少X-wave仿真运算时间，并为降低X-wave的硬件成本提供空间。结论该方法可以在较高精度的前提下显著降低X-wave的仿真成本，为X-wave的应用提供一种新思路。

Objective X-wave is a particular case of limited diffracting waves which has great application potential for field focus depth enlargement in acoustic imaging systems. In practice, the generation of real-time X-wave fields needs complex technologies and expensive hardware which involve precise and specific voltage time distributions for the excitation of each distinct array element. We proposed an approach for simplifying the generation process by approximating the X-wave excitations with rectangular or triangle pulses. Methods Simple driving pulses (rectangular and triangular) are cheap and easy to realize. The differences between theoretical X-wave signals and each driving pulse are minimized by L2 curve criterion separately. The pulse with the minimal optimization result is chosen as the approximation driving pulses. Results Simulation test shows that the new method can achieve more precise results than the original method and is closer to the theoretical X-wave result. The tradeoff is obtained between the cost of implementation of classical zero-order X-wave and the precision of approximation. Conclusions The new approach proposes a low-cost limited-diffraction wave generation and a new idea for the application of X-wave.

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