For more detailed measurement of cardiovascular motion and complex blood flow, a two-dimensional (2D) velocity estimation method is required in functional ultrasound imaging. The block matching method based on the correlation function is one of the standard 2D motion estimators. In this study, we investigated the effect of lateral sampling intervals of an ultrasonic B-mode image on the accuracy in velocity estimation. In simulation, bias error (BE) in estimated velocities became −13% with an ultrasonic center frequency of 7.5 MHz and spacings of receiving beams of 0.2 mm. Such a BE was improved from −13% to −1.4% by changing the spacings from 0.2 to 0.1 mm. In the in vivo experiment, the maximum velocity obtained with spacings of 0.2 mm was underestimated by −16% as compared to those obtained with 0.1 mm. Hence, the trend was similar to that in the simulation.

为了更详细地测量心血管运动和复杂的血流，在功能超声成像中需要二维 (2D) 速度估计方法。基于相关函数的块匹配方法是标准的二维运动估计器之一。在这项研究中，我们研究了超声波 B 模式图像的横向采样间隔对速度估计精度的影响。在仿真中，当超声中心频率为 7.5 MHz 且接收波束间距为 0.2 mm 时，估计速度的偏差误差 (BE) 变为 -13%。通过将间距从 0.2 更改为 0.1 毫米，这种 BE 从 -13% 提高到 -1.4%。在体内实验中，与使用 0.1 mm 获得的最大速度相比，以 0.2 mm 的间距获得的最大速度被低估了 -16%。因此，