本研究的主要目的是將由磁振顯影法（MRI, Magnetic Resonance Imaging）所量測得到的人體肢段組織分佈資料植入3D人體表面資料中，並用以估算生物力學參數，這些生物力學參數包括質量、質心、密度、轉動慣量以及轉動慣量半徑。本研究中所使用的3D人體表面資料是採用3D人體銀行中的資料，且該資料庫是由Gmini 3D量測儀所量得之3D人體表面資料所建構而成。
這些3D人體表面資料會先分割成若干肢段，分割好的肢段再比照MRI所量得的切片截面資料沿長軸等分切出相等數量的截面，並使其成對排列。接著將每對3D人體表面資料的肢段截面與MRI所量得的切片截面依照其X軸及Y軸對準，然後將MRI所量得的切片截面疊合至3D人體表面資料的肢段截面上。首先，骨骼的位置會先決定，且形狀不變；接著將MRI所量得的切片截面的表皮輪廓調整至與3D人體表面資料的肢段截面的輪廓重合 (當然肌肉的面積與形狀亦會隨輪廓而改變)。接著再等比例放大或縮小該肌肉形狀，使其面積與MRI所量得的切片截面上的肌肉面積相等。最後，當骨骼、肌肉與表皮的位置都已經確定，則肌肉的輪廓與表皮的內層輪廓之間的部份，便是脂肪。在這個截面上，我們可以簡要地分類出四種組織密度，分別為骨骼（1.579 g/㎜³）、肌肉（1.092 g/㎜³）、脂肪（0.937 g/㎜³）與表皮（1.06 g/㎜³），經由這些密度我們便可以得到此截面上的質量分布圖（mass distribution profile）。
當完成肢段上所有的質量分布圖以後，我們便將這些截面一一照其X軸及Y軸對準並沿長軸排列，進行肢段重建。最後，重建完成的肢段將會被細分為許多極微小的立方體，並且每一立方體的質量皆由其所屬的組織密度所決定，如此便可用以計算生物力學參數。

關鍵字：磁振顯影法（MRI, Magnetic Resonance Imaging），3D人體銀行(3D Body Bank)，質量分布曲線（Mass Distribution Profile）

The purpose of this study is to map 3D tomographical data obtained from MRI onto 3D human surface data for the computation of biomechanical parameters. These biomechanical parameters include mass, center of mass, averaged density, moment of inertia and radius of gyration. The 3D human surface data is the 3D Human Body Bank which was measured using 3D body scanners.
The profiles of four tissues, bone, skin, muscle and fat are mapped. The surface data of the segment is dissected into several equally-spaced cross-sections along its longitudinal axis like that of the MRI tomographical cross-sectional diagrams. For each pair of cross-sections, the profile of the tomographical data is superimposed on the surface data, and registered and aligned. First, the bone of MRI is directly mapped onto surface data. Second, the skin profile is deformed to match the contour of surface data. Then, profile of muscle is re-scaled in order to maintain the same size as that of the tomographical data. The area bound between the skin and the muscle is considered as fat. The new cross-section consists of a profile with 4 tissues of different densities, bone 1.579, muscle 1.08, skin 1.06, and fat 0.937. This is used to derive the mass distribution profile of the cross-section.
Upon the completion of all the distribution profiles for the segment, these cross-sections are used to re-construct into a solid segment. The final solid segment is then finally dissected into infinitesimal solid lattices of mass distribution for the computation of biomechanical parameters.

Keywords: MRI (Magnetic Resonance Imaging), 3D Human Body Bank, Mass distribution profile

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