基于电磁式位置传感器的超声三维成像系统中的定标方法

Calibration of 3D ultrasound imaging system based on magnetic position sensor

为在基于电磁式位置传感器的三维超声成像系统中 ,准确而快速地寻找到电磁式定位系统中接收器与图像平面间的空间关系 ,设计了一种利用三棱锥 /四棱锥模型的几何特性来计算定标参数的方案。这种新方法不仅减小了超声束在远场发散对定标精度的影响 ,而且提高了定标效率。物理实验证明系统在稳定性。

The 3D freehand ultrasound imaging system is a new technology that is rapidly finding clinical applications due to its convenience. This paper describes the general structure of the 3D ultrasound imaging system based on a magnetic position sensor. Some existing calibration procedures are then analyzed. The calibration process can be quickened with a novel pyramid phantom that is used to determine the position and orientation of the B scan image with respect to the position sensor. This pyramid method not only reduces the effect of the thickness and divergence of the ultrasound beam, but also greatly improves the test efficiency. Physical experiments show that the new system has good stability, precision and accuracy for 3D reconstruction.