Howarth Samuel J, Callaghan Jack P
Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
Comput Methods Biomech Biomed Engin. 2010 Dec;13(6):847-55. doi: 10.1080/10255841003664701.
Marker obstruction during human movement analyses requires interpolation to reconstruct missing kinematic data. This investigation quantifies errors associated with three interpolation techniques and varying interpolated durations. Right ulnar styloid kinematics from 13 participants performing manual wheelchair ramp ascent were reconstructed using linear, cubic spline and local coordinate system (LCS) interpolation from 11-90% of one propulsive cycle. Elbow angles (flexion/extension and pronation/supination) were calculated using real and reconstructed kinematics. Reconstructed kinematics produced maximum elbow flexion/extension errors of 37.1 (linear), 23.4 (spline) and 9.3 (LCS) degrees. Reconstruction errors are unavoidable [minimum errors of 6.7 mm (LCS); 0.29 mm (spline); 0.42 mm (linear)], emphasising careful motion capture system setup must be performed to minimise data interpolation. For the observed movement, LCS-based interpolation (average error of 14.3 mm; correlation of 0.976 for elbow flexion/extension) was most suitable for reconstructing durations longer than 200 ms. Spline interpolation was superior for shorter durations.
在人体运动分析过程中，标记物遮挡需要进行插值以重建缺失的运动学数据。本研究对与三种插值技术以及不同插值持续时间相关的误差进行了量化。对13名参与者在手动轮椅坡道上升过程中的右尺骨茎突运动学数据进行了重建，使用线性、三次样条和局部坐标系（LCS）插值方法，插值范围为一个推进周期的11%-90%。使用真实和重建的运动学数据计算肘部角度（屈伸和旋前/旋后）。重建的运动学数据产生的最大肘部屈伸误差分别为37.1度（线性）、23.4度（样条）和9.3度（LCS）。重建误差是不可避免的[最小误差分别为6.7毫米（LCS）；0.29毫米（样条）；0.42毫米（线性）]，这强调了必须仔细设置运动捕捉系统以尽量减少数据插值。对于观察到的运动，基于LCS的插值（平均误差为14.3毫米；肘部屈伸的相关性为0.976）最适合重建持续时间超过200毫秒的数据。样条插值在较短持续时间内表现更优。
