Bohs L N, Friemel B H, McDermott B A, Trahey G E
Department of Biomedical Engineering, Duke University, Durham, NC 27706.
Ultrasound Med Biol. 1993;19(9):751-61. doi: 10.1016/0301-5629(93)90092-3.
This paper describes a system that has been developed for measuring two-dimensional velocities in real time using ultrasound. The instrument tracks interframe speckle pattern motion using a Sum-Absolute-Difference (SAD) algorithm in order to produce a vector map of 2D velocities. The system's parallel architecture allows calculation of approximately 20,000 vectors per second using the current tracking geometry. A programmable graphics processor encodes individual velocity vectors with color and displays them superimposed on the B-mode image in real time. In vitro tests indicate that the system can track velocities well over the Doppler aliasing limit in any direction in the scan plane with greater than 94% accuracy. A color encoded image obtained from a flow phantom highlights the system's ability to display lateral motion with uniform coloration, in contrast to the two-color display of current ultrasonic Doppler instruments.
本文描述了一种利用超声波实时测量二维速度的系统。该仪器使用绝对差分求和（SAD）算法跟踪帧间散斑图案运动，以生成二维速度矢量图。系统的并行架构允许使用当前跟踪几何结构每秒计算约20,000个矢量。可编程图形处理器用颜色对各个速度矢量进行编码，并实时将它们叠加显示在B模式图像上。体外测试表明，该系统能够在扫描平面的任何方向上以超过94%的准确率跟踪远高于多普勒混叠极限的速度。从流动模型获得的彩色编码图像突出显示了该系统以均匀颜色显示横向运动的能力，这与当前超声多普勒仪器的双色显示形成对比。
