人體動作分析皮膚移動誤差量測之研究

人體動作分析是用來估計肌肉、骨骼與關節疾病或傷害時相當重要的方式，紅外立體攝影術是目前最常使用來量測人體活動的非侵入性方法。而皮膚移動誤差是此方法最主要的誤差來源，它進一步將造成肢部座標系統定義偏差。截至目前為止，並沒有一個研究一系列量化皮膚移動誤差、觀察運動學及力動學受到皮膚移動誤差之影響。本研究的目的在於結合三維電腦模型以及二維動態X光影像重建模型空間位置，以提供準確的非侵入式的人體三維動態活體量測方法。本方法具有三維、活體、動態、非侵入式、準確等優點。透過動態X光(fluoroscopy)取得動態關節影像，藉由電腦斷層掃瞄用來重建完整肘關節之三維幾何骨模型，而由電腦輔助設計之模型取得人工膝關節三維幾何構件模型，藉由影像契合(image registration)等技術，找出實驗時骨骼正確之空間位置及方向，當作為黃金標準(gold standard)。本研究目的在於量化皮膚移動誤差並觀察皮膚移動誤差對角度的影響，同時搭配測力板取得力學資訊來計算力動學受到皮膚移動誤差的影響。使用前臂座標系統定義在前臂旋前/旋後動作中所計算出來的角度會比較不敏感，並不能完全的表示前臂真正的運動，而在做精確的上肢動作分析時，些微的偏差可能就會造成極大的誤差。因此根據研究結果可以提供一組建議的標記組來避免皮膚移動誤差。膝關節在屈曲時所產生的角度特別在矢狀面上角度與力矩誤差較大，在計算關節力矩時也可以使用完整的下肢自由體分析，會比舊有研究只利用力板向量與關節軸心的資料計算來的更加完善。未來，希望能應用我們所發展的方法，量測不同關節及其他骨骼肌肉系統疾患，進一步研究有關皮膚移動誤差之補償法，甚至可以研究各式模型受到皮膚移動誤差的影響。

關鍵字

皮膚移動誤差；運動學；力動學；動態Ｘ光；電腦骨骼模型；動作分析

並列摘要

The human motion analysis is essential for assessing musculoskeletal & joint disease or injury. Infrared stereophotogrammetry is currently the most common non-invasive method for the measurement of human motion. It is to determinate the spatial position and to get the understanding human body extremity section movements. Soft tissue artifacts (STA) are the most important errors in this method. If the STA are not able to be handled effectively, it will further create the deviation of the definition of the extremity section coordinates systems. The new method used the three dimension models (reconstructed from serial computer tomography images or the computer-aided design model) to register with two-dimensional (2D) fluoroscopic images during motion. Motion data of the markers on the extremity were also measured simultaneously using the motion analysis system. With the exact 3D position and orientation of the bones during motion, the STA can be determined using coordinates transformation of the skin markers. Hence, the purposes of this study were to quantify the STA, and to obtain the errors of the joint angles and moment. The angle calculated by fore-arm coordinates system was not sensitive during pronation/supination motion. It can’t totally exhibit the true motion and it will cause huge errors when we analyzed the upper-limb motion. Therefore, it can provide a set of markers to avoid soft tissue artifact. In addition, there are large errors in joint angles and moments in the sagittal plane. In this study, we utilized complete lower-limb free body analysis that will be more faultless than previous study which only used the ground reaction force and the knee joint axis to calculate the joint moment. In the future, the method we develop will be adopted in other joint components and be extended in studying various kinds of diseases. Furthermore, we can study the compensation methods and the effects of coordinate system definition by soft tissue artifact.

並列關鍵字

Soft tissue artifact ； Kinematics ； Kinetics ； Fluoroscopy ； Computer bone model

參考文獻

Andriacchi, T. P. and E. J. Alexander (2000). "Studies of human locomotion: past, present and future." J Biomech 33(10): 1217-24.

Barth, W. (1999). "Significance of knee joint loads calculated using inverse dynamics " PhD Thesis, Swiss Federal Institude of Technology, Zurich.

Benoit, D. L., D. K. Ramsey, et al. (2006). "Effect of skin movement artifact on knee kinematics during gait and cutting motions measured in vivo." Gait Posture 24(2): 152-64.

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人體動作分析皮膚移動誤差量測之研究

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