Correcting for deformation in skin-based marker systems
Correcting for deformation in skin-based marker systems
复制标题
DOI：
10.1016/s0021-9290(00)00192-5
复制
发表时间：
2001-03-01
影响因子：
2.4
通讯作者：
Andriacchi, TP
中科院分区：
文献类型：
--
作者：
Alexander, EJ;Andriacchi, TP
介绍了一种在活体骨骼运动的光电测量中减少皮肤运动伪影引起的误差的新技术。这项工作建立在前面描述的点簇技术、标记集和估计算法的基础上，通过使用一组依赖于活动的变形模型将变换方程扩展到一般变形情况。将日常生活活动中的皮肤变形建模为在观察间隔内定义的函数形式(变形模型)加上加性噪声(建模误差)。该方法被描述为区间变形技术。通过将变形误差的系统分量和随机分量引入标记位置向量的模拟试验，对该方法进行了测试。研究发现，这项技术的性能大大优于需要刚体假设的方法。该方法在一名装有外固定装置(Ilizarov)的患者身上进行了活体测试。将放置在Ilizarov装置(固定在骨骼上)上的标记物的同时测量结果与来自皮肤标记物的测量结果进行比较。与经典的刚体姿态估计方法相比，区间变形技术使肢体段姿态估计的误差分别降低了33%和25%。这一新开发的方法表明，通过考虑肢体节段形状的变化，可以实现对活体骨骼运动的估计的实质性改进。(C)2001爱思唯尔科学有限公司。保留所有权利。
A new technique is described that reduces error due to skin movement artifact in the opto-electronic measurement of in vivo skeletal motion. This work builds on a previously described point cluster technique marker set and estimation algorithm by extending the transformation equations to the general deformation case using a set of activity-dependent deformation models. Skin deformation during activities of daily living are modeled as consisting of a functional form defined over the observation interval (the deformation model) plus additive noise (modeling error). The method is described as an interval deformation technique. The method was tested using simulation trials with systematic and random components of deformation error introduced into marker position vectors. The technique was found to substantially outperform methods that require rigid-body assumptions. The method was tested in vivo on a patient fitted with an external fixation device (Ilizarov). Simultaneous measurements from markers placed on the Ilizarov device (fixed to bone) were compared to measurements derived from skin-based markers. The interval deformation technique reduced the errors in limb segment pose estimate by 33% and 25% compared to the classic rigid-body technique for position and orientation, respectively. This newly developed method has demonstrated that by accounting for the changing shape of the limb segment, a substantial improvement in the estimates of in vivo skeletal movement can be achieved. (C) 2001 Elsevier Science Ltd. All rights reserved.