2-D motion estimation using two parallel receive beams
2-D motion estimation using two parallel receive beams
复制标题
DOI：
10.1109/58.911722
复制
发表时间：
2001-03-01
影响因子：
3.6
通讯作者：
Trahey, GE
中科院分区：
文献类型：
--
作者：
Bohs, LN;Gebhart, SC;Trahey, GE
本文描述了一种利用超声估计二维目标运动的方法。该方法基于先前的集成跟踪技术，该技术需要至少四个平行接收波束和二维模式匹配。相比之下，所描述的方法只需要两个平行的接收光束和一维模式匹配。执行两个一维搜索，每个方向一个横向搜索。产生最佳匹配的方向表示运动的横向方向。插值提供亚像素级的分辨率。在三种不同的平行光束转向角度和换能器角度分别为0度、45度和90度的情况下，采用平移散斑目标，比较了双波束方法和四波束方法。最大的差异是在90度处发现的，在那里，两束方法通常比四束方法更准确和精确，并且在小的翻译中也更不容易出现方向错误。我们还研究了这两种方法在层流模型中的性能。结果表明，在流速较小时，双光束法测量气流角的精度较高。计算机模拟支持实验结果。四梁方法性能较差的原因是平行梁之间的相关性存在差异。具体来说，中心梁2和3之间的相关性比与外部梁更好。由于四波束方法将波束对2-3中的核区域与两个不同的波束对1-2和3-4进行比较，这种比较的2比1和3比4分量增加了方向误差的发生率，特别是在小平移时。双光束法只使用两束光束之间的比较，因此不受这个误差来源的影响。最后，当选择与发射轴对称的两束时，两束方法不需要像四束方法那样需要幅度归一化。我们得出结论，双光束系综跟踪可以准确地估计运动，仅使用两个平行的接收光束。
We describe a method for estimating 2-D target motion using ultrasound. The method is based on previous ensemble tracking techniques, which required at least four parallel receive beams and 2-D pattern matching. In contrast, the method described requires only two parallel receive beams and 1-D pattern matching. Two 1-D searches are performed, one in each lateral direction. The direction yielding the best match indicates the lateral direction of motion. Interpolation provides sub-pixel magnitude resolution. We compared the two beam method with the four beam method using a translating speckle target at three different parallel beam steering angles and transducer angles of 0, 45, and 90 degrees. The largest differences were found at 90 degrees, where the two beam method was generally more accurate and precise than the four beam method and also less prone to directional errors at small translations. We also examined the performance of both methods in a laminar flow phantom. Results indicated that the two beam method was more accurate in measuring the flow angle when the flow velocity was small. Computer simulations supported the experimental findings. The poorer performance of the four beam method was attributed to differences in correlation among the parallel beams. Specifically, center beams 2 and 3 correlated better with each other than with the outer beams. Because the four beam method used a comparison of a kernel region in beam pair 2-3 with two different beam pairs 1-2 and 3-4, the 2-to-1 and 3-to-4 components of this comparison increased the incidence of directional errors, especially at small translations. The two beam method used a comparison between only two beams and so was not subject to this source of error. Finally, the two beam method did not require amplitude normalization, as was necessary for the four beam method, when the two beams were chosen symmetric to the transmit axis. We conclude that two beam ensemble tracking can accurately estimate motion using only two parallel receive beams.