Hergum Torbjørn, Langeland Stian, Remme Espen W, Torp Hans
Department of Circulation and Medical Imaging, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), St. Olavs Hospital, Trondheim, Norway.
IEEE Trans Ultrason Ferroelectr Freq Control. 2009 Jun;56(6):1159-67. doi: 10.1109/TUFFC.2009.1158.
Most available ultrasound imaging simulation methods are based on the spatial impulse response approach. The execution speed of such a simulation is of the order of days for one heart-sized frame using desktop computers. For some applications, the accuracy of such rigorous simulation approaches is not necessary. This work outlines a much faster 3-D ultrasound imaging simulation approach that can be applied to tasks like simulating 3-D ultrasound images for speckletracking. The increased speed of the proposed simulation method is based primarily on the approximation that the point spread function is set to be spatially invariant, which is a reasonably good approximation when using polar coordinates for simulating images from phased arrays with constant aperture. Ultrasound images are found as the convolution of the PSF and an object of sparsely distributed scatterers. The scatterers are passed through an anti-aliasing filter before insertion into a regular beam-space grid to reduce the bandwidth and significantly reduce the amount of data. A comparison with the well-established simulation software package Field II has been made. A simulation of a cyst image using the same input object was found to be in the order of 7000 times slower than the presented method. Following these considerations, the proposed simulation method can be a rapid and valuable tool for working with 3-D ultrasound imaging and in particular 3-D speckle-tracking.
大多数现有的超声成像模拟方法都基于空间脉冲响应方法。使用台式计算机对一个心脏大小的帧进行这种模拟的执行速度约为数天。对于某些应用，这种严格模拟方法的准确性并非必要。这项工作概述了一种速度快得多的三维超声成像模拟方法，该方法可应用于为散斑跟踪模拟三维超声图像等任务。所提出的模拟方法速度的提高主要基于将点扩散函数设置为空间不变的近似，当使用极坐标模拟具有恒定孔径的相控阵图像时，这是一个相当不错的近似。超声图像是点扩散函数与稀疏分布散射体的物体的卷积。在将散射体插入规则的波束空间网格之前，先通过一个抗混叠滤波器，以降低带宽并显著减少数据量。已与成熟的模拟软件包Field II进行了比较。使用相同输入对象对囊肿图像进行模拟，结果发现比所提出的方法慢约7000倍。基于这些考虑，所提出的模拟方法可以成为处理三维超声成像特别是三维散斑跟踪的快速且有价值的工具。
