臺灣博碩士論文加值系統

摘 要
現代人花費很多的時間坐在椅子上，如果長時間的坐姿不良，會導致很多脊椎方面的問題，如：椎間盤突出、慢性腰痛病(Low Back Pain)等[24]，情況輕者可藉由復健科醫師施以熱敷(Hot Pack)或利用機器的牽引(Traction)來加以治療，而嚴重者可能就要進行外科手術來加以矯正並進行復健。在現今電腦圖形處理技術的進步驅使下，模擬人體與真實環境的互動便可藉由虛擬實境技術(Virtual Reality Technology)[7]來加以實現，在本論文中我們實作了人體脊椎的運動模擬系統。藉由控制對脊椎椎骨所施加的外力，我們可觀察各椎骨產生相對角度變化的反應，並了解脊椎的可能運動模式及其在復健上所施行的方法、步驟對人體所造成的影響。在結合電腦圖學、虛擬實境技術、脊椎背景知識及生物力學為基礎下，本系統一方面可提供給復健科醫師做為復健過程的演練、學習；同時，也可藉由本系統的模擬，提供病人做為復健姿勢的認識與了解，使之明瞭復健的每一過程和步驟在實際應用於脊椎的推拿、牽引等所產生的療效與作用；在另一方面，我們也可利用此系統的建立，增加對脊椎運動模擬中各項參數的了解，這將有助於人體運動模擬平臺的建立及人體替代性關節的研發與設計。
本系統使用物件階層(Object Hierarchy)的觀念來做為整個模擬架構的基礎，因此模型中的各種元件可以很容易地被替換、擴展及再使用(Reuse)，在實作上具有高度的彈性。其中，我們利用了部份生物力學的觀念，在虛擬實境軟體[36]的輔助下建立了脊椎運動模擬的架構、參數以及環境設定，來模擬人體脊椎每一塊椎骨的受力情形、及其產生相對應位移、角度變化等作用，並且包括頭頸部運動的展示功能。首先，我們將身體的每一塊椎骨視為一獨立物件，相連椎骨間依照生物力學(Biomechanics)的特性可組合成更大的物件，再依照關節間的連結性質將整個脊椎構造出來。接下來，為了建立人體模型產生互動的機制，我們沿用了事件驅動的模式(Event-driven Paradigm)，透過此模擬系統中所設定三種「力與相對角度變化」的計量模式，來模擬人體脊椎受力的作用而產生位移及角度旋轉等變化，並在虛擬實境的環境下展示。第一種模式是以單純的遞減方式模擬脊椎受力後產生的角度變化，這是個簡化的運動模式，此模式提供我們觀察脊椎在此自由度(Degree of Freedom)拘束下所產生椎骨間角度變化的模擬。在第二種模式中，我們使用分段遞減模式來取代上述模式的部份參數，目的除了使不同段的椎骨(如：頸椎、胸椎、腰椎)具有較一致的特性外並簡化參數的調整。第三種模式則利用虛功原理(Virtual Work)等物理學概念，對脊椎受力情形作空間上的分析，並藉由連桿(Linkage)模型獲得脊椎所產生空間各軸的相對角度變化。最後，我們對此三種模式提出一些模擬上的分析及展示，並探討可能的改進做法。因為受限於現實環境的資料取得困難，我們無法確實得知脊椎椎骨運動時的真實位置與方向，而以模擬方式來呈現出脊椎的運動模式，並透過醫生對此模擬系統的主觀看法加以評估。未來，我們希望可以結合更多的儀器設備之助，取得人體脊椎相關量測資料，作為我們實驗及分析的客觀依據，並將此脊椎運動模擬所用的參數資料及環境設定，提供人體其他部位的關節或機器人的運動模擬，以做為實作上的參考，另外也可提供人工關節在設計上的考量及模擬。

Abstract
Virtual Reality (VR) technology has been widely used to develop popular tools for simulating the real life circumstances. For most applications, VR acts as the role of an interaction mechanism between computers and participants. This thesis looks into the field of kinematics simulation of the spine by means of VR technology, computer graphics, Biomechanics, and fundamentals on the spine. First, we survey some character/human animation software and motor control systems. Most of these widgets are deficient in interactions. To have a more realistic presentation of spinal movement and interaction, we use an object hierarchy for the whole simulation while constraints on spine are maintained. Our system outlines the general human structures and follows the event-driven paradigm to construct the simulation system, which is implemented by one of the three methods to generate the relative angular variations after applying a force on the spine.
As VR is proven to be an effective educational tool, experienced doctors can use our system to instruct the juniors how a force impact influences spinal movement. Additionally, therapists can also tutor patients in spinal rehabilitation. In our system, we model a spine using 24 vertebrae and 25 joints, and form the linkages in a resting shape. Each vertebra maintains a set of local parameters. These parameters reflect the exterior factors on spinal movement and allow adequate calibration in our virtual world. We also provide some rules and criteria for coarse tuning of parameters. The first two methods of our system are simplified ones in which we make some assumptions of the relative angular variations resulted from applying a force upon the spine. The third method is partially based on physical rules and adopts the "virtual work" concept to calculate the angular variations. In short, we treat the entire vertebrae as a multi-segment linkage and use Statics to solve the problem. By repeatedly exerting a force on a vertebra, we can observe the spinal movement at any viewpoint in a 3-D space. We also show neck-head movement using the experimental data from 3D Motion Analyzer.
It is not easy to find the optimal parameter setup in our system because some biometrics measurements of the spine are not readily available. However, we can approximate spinal movement with manual involvement and guidance from doctors. Our system can gradually adapt to other applications by substituting suitable geometric models, processing units and parameters. It can also contribute to the progress of artificial joint design. Our objective is not to mimic the actual spinal movement, but rather to provide a flexible skeletal platform for human movement simulation. In our future research, we will try to combine the muscular system with our skeletal system and use data gathered from instruments to verify the quantitative analysis and evaluation.

目 錄
摘 要 I
ABSTRACT III
目 錄 V
圖 表 目 錄 VII
第1章 導論 1
1.1 研究動機及背景 2
1.2 研究主旨與方向 5
1.2.1 利用3D模型軟體建立脊椎的幾何形狀 6
1.2.2 建立虛擬實境場景與互動關係 7
1.2.3 脊椎運動模擬機制的產生 9
1.3 相關研究 9
1.3.1 動畫技術(Animation Techniques) 11
1.3.1.1 關鍵格技術(Key Frame Techniques) 11
1.3.1.2 動作攫取技術(Motion Capture Techniques) 14
1.3.1.3 混合式(Hybrid) 14
1.3.2 動畫軟體 14
1.3.3 碰撞偵測與力的回饋 17
1.3.4 分散式互動模擬(DIS: Distributed Interactive Simulation) 20
第2章 系統設計 22
2.1 系統架構 23
2.2 脊椎與生物力學 25
2.2.1 脊椎結構 25
2.2.2 生物力學(Biomechanics) 28
2.2.3 平衡控制(Balance Control) 32
2.2.4 脊椎活動限制 33
2.3 脊椎運動模式中三種計量模式的設計 35
2.3.1 遞減模式(Decrement Method) 35
2.3.2 分段遞減模式(Segmented Decrement Method) 37
2.3.3 力的分解模式(Force Decomposition Method) 38
2.4 系統介面與參數 42
第3章 系統實作 44
3.1 硬體設備 44
3.2 軟體設備 45
3.3 系統流程 48
3.4 應用：頭頸部動作模擬 50
第4章 模擬結果及評估 52
4.1 脊椎運動展示 53
4.1.1 使用者介面 54
4.1.2 遞減模式展示 56
4.1.3 分段遞減模式展示 58
4.1.4 力的分解模式展示 60
4.1.5 頭頸部運動模擬展示 61
4.2 系統評估 64
4.2.1 主觀評估與比較 65
4.2.2 客觀上的考量 65
4.3 系統改進 66
第5章 結論與未來展望 68
5.1 結論 68
5.2 未來展望 69
參考文獻 71
圖 表 目 錄
圖1-1. 椎骨與力的互動關係描述(以事件為觀點) 8
圖1-2. 椎骨與力的互動關係圖 8
圖1-3. 人體運動單元 (取自Fractal Design Poser Version 2.0) 13
圖1-4. 關鍵格技術(取自Fractal Design Poser Version 2.0) 13
圖1-5. 逆關節運動(IK)圖示 16
圖1-6. 人體的階層概念 17
圖1-7. 碰撞偵測與物體幾何形狀的關係 19
圖2-1. 系統開發流程圖 23
圖2-2. 系統架構中的事件轉移 24
圖2-3. (A) 典型的頸椎、胸椎及腰椎；陰影的部份為兩相鄰椎骨接觸的小平面(Facets)，其角度在頸椎約略從 到腰椎幾乎垂直 (B) 脊椎功能單元(FSU) (C) FSU關節 26
圖2-4. 脊椎的外觀：(A) 正面觀 (B) 背面觀 (C) 側面觀 27
圖2-5. 人體運動回饋系統 30
圖2-6. 人體運動回饋系統(簡化) 31
圖2-7. 關節與槓桿原理 31
圖2-8. 影響平衡的子系統 33
圖2-9. 各椎骨在空間中的角度活動範圍 34
圖2-10. 系統設定 35
圖2-11. 遞減模式 36
圖2-12. 分段遞減模式範例 - 各椎骨的角度變化量 (力作用於胸椎T6) 38
圖2-13. 力的分解模式設定 39
圖3-1. SpaceBall Technologies SpaceBall 2003 44
圖3-2. dVS Architecture 46
圖3-3. 分散式處理範例 (將Visual Actor透過網路分散給其它主機處理) 47
圖3-4. 多使用者，多主機之設定 47
圖3-5. 系統流程(一)：幾何處理程序 48
圖3-6. 系統流程(二)：互動行為描述 - 事件流程 49
圖4-1. 人體脊椎運動模擬系統之初始設定 52
圖4-2. 利用三視圖所繪製的椎骨(T7)模型 52
圖4-3. 使用者介面 - 工具箱 55
圖4-4. 使用者介面 - 交談介面 55
圖4-5. (A)(B) 使用者介面 - 控制台 55
圖4-6. 各椎骨的角度變化量 - 遞減模式 57
圖4-7. 連續五次施力作用於T6 - 遞減模式 57
圖4-8. 虛擬實境中模擬人體脊椎運動 - (由A到H) 58
圖4-9. 各椎骨的角度變化量 - 分段遞減模式 59
圖4-10. 連續五次施力作用於T6 - 分段遞減模式 59
圖4-11. 頭頸部資料初始設定 62
圖4-12. 頭頸部資料展示：(A)水平旋轉(Rotation) (B)前彎(Flexion) 62
圖4-13. 頭頸部資料展示 - 使用者介面 63
圖4-14. (A)(B)(C)分別表示X、Y、Z軸在取樣橫軸上所對應的旋轉角度 64
圖4-15. 頭頸部在空間三軸的旋轉角度值 64
表1. 身體前傾角度與椎間盤所承受壓力的關係 28
表2. 遞減模式腰椎參數設定範例 37
表3. 當L4受到2單位外力作用時 37
表4. 三種角度計算模式的參數比較 43
表5. 脊椎的初始角度設定 53
表6. 分段遞減模式參數 - 力作用於胸椎T6 58
表7. 力的分解模式之參數設定 61

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