基于薄板样条函数的电磁定位系统位姿校正方法

电磁定位系统（EM）凭借其精度高、反应灵活、操作简便、价格便宜以及无遮挡效应等优点，被广泛应用于各种需要进行跟踪定位的领域。在介入手术中，EM可以很好地解决因人体组织对介入器械的遮挡而无法进行精确光学定位的问题，能够对介入器械的位姿进行精确定位。但EM是通过电磁感应原理对介入器械进行跟踪定位，因此手术环境中存在的铁磁性物质产生的干扰磁场会导致EM的磁场产生畸变，从而影响其定位精度。对EM的定位原理进行了分析，通过分析EM受干扰前后传感器在相同位置的位姿变化，提出一种基于薄板样条函数的电磁定位系统校正方法，对EM受干扰后的位姿进行校正，并通过实验验证该方法的有效性。

A thin plate spline based method for correction of position and posture of electromagnetic tracking system

Electromagnetic tracking system (EM) is widely used in various environments needing tracking or positioning, due to its high accuracy, flexible reaction, simple operation, cheap price and insensitivity to blocks. In vascular interventional surgery, EM performs well in clinical environment with inaccurate optical positioning due to tissue occlusion. However, EM suffers a lot from the principle of electromagnetic induction which makes it sensitive to ferromagnetic material, like steel. The magnetic field generated by ferromagnetic materials in the operation environment will cause the distortion of the magnetic field of EM, which affects the positioning accuracy seriously. In this paper, the positioning principle of EM is analyzed. By analyzing the position and orientation changes of sensors at the same position before and after the EM interference, a correction method of the electromagnetic tracking system based on the thin plate spline function is proposed to correct the position and posture of the EM after interference.The effectiveness of our method is verified by experiments.