上肢動作之皮膚移動誤差量測

Abstract

截至目前為止，並沒有一種量測方法可以在非侵入式的情況下，正確量測上肢運動學資料，立體攝影術最大誤差來源是皮膚移動誤差，為了取得活體上肢肘關節三維運動學正確資料。本研究的目的便是運用正確量測方法，準確得到上肢活動之皮膚移動誤差。 本研究使用動態X光（fluoroscopy）配合電腦骨骼模型，量測活體關節運動學；透過動態X光取得動態關節影像，運用電腦斷層掃瞄得到骨骼之斷面影像，可用來重建完整肘關節之三維幾何模型，再搭配動作分析（motion analysis）、影像處理（image processing）與影像契合（image registration）之技術，找出實驗時骨骼正確之空間位置及方向。另外經由座標轉換計算出反光標記相對於骨骼局部座標系統之座標值改變，不僅獲得立體攝影術中使用皮膚標記所造成的皮膚移動誤差，又可獲得人體肘關節三維運動學資料、尺骨與橈骨之間相對運動，進而找出正確的肘關節、尺骨與橈骨間運動學機制。 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，以利未來骨科、復健科、物理治療、職能治療、運動醫學、電腦輔助手術與人工關節設計等領域的進步。

The upper limb motions are essential in daily activities. Knowledge of the kinematics of the upper limb is essential for the understanding of its function. To the best knowledge of the author, no study has investigated the in vivo kinematics of the upper limb using non-invasive method. The major source of error in human motion analysis is soft tissue artifact (STA). There is still a very limited amount of existing literature on STA measurement of the upper limb motions. The purposes of the study were to use a non-invasive method for the determination of three-dimensional (3D) dynamic skeletal motions in vivo using fluoroscopy and to apply this method to measure STA of the upper limb motions. The new method involves the match of two-dimensional (2D) fluoroscopic images of the upper limb during motion with projections of the computer upper limb models reconstructed from serial computer tomography images. The 3D upper limb position that produced best-matched projection with the fluoroscopic image was then taken as the special position of the tested upper limb. Through techniques of 3D upper limb computer geometric model reconstruction, motion analysis, image processing and image registration. The upper limb kinematics function and relative motions between humerus, radius and ulna can be found. Further more, soft tissue artifact can be measured with transforming of the coordinate systems of markers that attached to the upper limb in stereo-photogrammetry. In the future, we hope that it will be helpful in orthopedics, rehabilitation, physical therapy, occupational therapy, medicine of sports and computer-aided surgery with the application of this method on motions of varies joints.