一种提高N线模型探头标定精度的解算方法  

A Calculation Method to Improve the Accuracy of N-Phantom Based Probe Calibration

作　　者：朱立人[1] 李文骏[1] 丁辉[1] 王广志[1] 

机构地区：[1]清华大学医学院生物医学工程系,北京100084

出　　处：《中国生物医学工程学报》2012年第3期337-343,共7页Chinese Journal of Biomedical Engineering

基　　金：国家重点基础研究发展计划(973计划)(2011CB707701);国家自然科学基金仪器专项(81127003);清华大学自主科研计划

摘　　要：在超声引导的介入治疗中,为了利用三维定位系统实现对超声成像平面的跟踪,超声探头与定位系统的传感器之间几何关系的标定是影响整体引导精度的重要环节。广泛应用的N线模型和传统最小二乘解算方法在超声探头标定中存在注册点共面性丢失的问题,进而影响标定精度。针对这一问题,提出一种先拟合虚拟成像平面,再进行共面约束下标定的解算方案,以提高利用N线模型进行标定的精度。实际的标定实验结果表明,新的解算方法能够有效地解决共面性丢失带来的精度影响,与传统解算方法相比,标定误差从5.88 mm降低到4.11 mm。In ultrasound guided intervention,in order to track the ultrasonic imaging plane using a 3D spatial tracking device,a transform between ultrasound probe and the attached sensor of the tracking system has to be determined by calibration.The accuracy of calibration has significant impact on the overall accuracy of ultrasound guidance.The widely used N-phantom and traditional least square（LS） calculation method are troubled by lost of coplanar property of registration point set,and may not produce an accurate result.In this paper,a calculation method was presented to tackle this problem,and improve the accuracy of N-phantom based calibration.This calculation method firstly reconstructed the planarity of input point set,and then computed the transform using an LS algorithm with coplanar constraint.Calibration experimental results showed that the new method decreased calibration error to 4.11 mm compared with 5.88 mm of the conventional method.

关 键 词：超声引导介入治疗 超声探头标定 N线模型 最小二乘配准 

分 类 号：R318.08[医药卫生—生物医学工程]