Shattuck D P, Ophir J, Johnson G W, Yazdi Y, Mehta D
Department of Radiology, University of Texas Medical School, Houston 77030.
Ultrasound Med Biol. 1989;15(7):673-81. doi: 10.1016/0301-5629(89)90175-0.
The beam tracking approach to the estimation of the speed of sound has shown potential for making unbiased estimates in tissues. The speed of sound in a medium can be found from the arrival times of echoes as a function of the position of a tracking transducer. There is a problem in this approach if the angle between the direction of tracked beam and the direction of tracking translation is not zero due to refraction or other effects. An angle error as small as 1 degree would result in an error that is too large for diagnostic applications. A modified technique using three or more tracking transducers is described. This yields a corrected speed of sound estimate, and calculates the angle error. A simulation program has shown that this modified technique could indeed correct for the angle errors.
用于估计声速的波束跟踪方法已显示出在组织中进行无偏估计的潜力。介质中的声速可根据跟踪换能器位置的函数关系，从回波的到达时间得出。如果由于折射或其他效应，跟踪波束方向与跟踪平移方向之间的夹角不为零，那么这种方法就会存在问题。小至1度的角度误差会导致对于诊断应用来说过大的误差。本文描述了一种使用三个或更多跟踪换能器的改进技术。这会得出经校正的声速估计值，并计算角度误差。一个模拟程序表明，这种改进技术确实可以校正角度误差。
