基于三点法和ICP算法的手术导航系统患者配准

为提升手术导航系统的患者配准精度和操作效率，提出一种将三点法与迭代最近点(iterative closest point，ICP)算法相结合的配准策略.首先，定义患者配准问题，并介绍术前和术中数据获取方法；然后，以光学定位标记球心为患者空间与图像空间的共同特征，并利用三点法完成初始配准；最后，以经初始映射后的患者点云中各点为球心，建立半径为r的球形区域，并仅保留位于该区域内的图像点云以实现抽样，再利用改进ICP算法对两片点云执行精确配准.实验结果表明，采用所提方法对猪股骨和猪髂骨执行配准的平均误差分别为(0.83±0.10)mm和(0.86±0.09)mm，其精度和稳定性均优于传统ICP算法，且具备高效、易操作的特点以及潜在的临床应用价值.

Patient Registration for Surgical Navigation System Based on Three-Point Method and ICP Algorithm

To improve the accuracy and operation efficiency of patient registration for the surgical navigation system， the registration strategy which combined three-point method and iterative closest point (ICP) algorithm was proposed. Firstly， the patient registration problem was defined and the acquisition methods of preoperative and intraoperative data were introduced. Then， the spherical center of the optical positioning markers were taken as the common features between patient space and image space， and the initial registration was completed by using the three-point method. Finally， the spherical regions with radius r were established by taking each point of patient point cloud after initial mapping as the spherical center， and the points of image point cloud located in these regions were retained to realize sampling， and the improved ICP algorithm was used to perform accurate registration of the two point clouds. The experimental results showed that the mean registration errors for pig femur and pig ilium when using the proposed method are (0.83±0.10)mm and (0.86±0.09)mm， respectively， which is superior to the traditional ICP algorithm in terms of accuracy and stability， and is efficient and easy to operate with certain potential values in clinical applications.