在齒顎矯正方面，石膏牙模提供牙醫師有關病患診斷與治療的重要資訊，但因石膏牙模易脆且儲存不易，以至於管理不便，電腦化也許可以提供解決此問題之方法。本研究利用陰影造形重建法，將牙模重建出三維立體數位模型，通常此一方法有拍攝光源不均勻的問題，這是造成重建結果不準確的最主要原因之一，因此本研究應用發光二極體陣列作為光源，提供一個均勻且穩定的光源；再者光線強度衰減也是產生重建高度誤差原因之一，本研究從實驗取得校正曲線並加以實現，以提高重建準確度；由於陰影造形重建法只能重建物體打光可見面，因此本研究也利用影像對位與影像整合，採用亮度作為高度權重方法，將多個從不同角度所獲得之三維資訊加以整合建構出單一完整模型；最後比較此重建牙模與雷射掃瞄牙模結果，本研究所研發系統可以明顯改進重建牙模之誤差分布在+0.57 mm至-0.95 mm之間。

In orthodontics, the dental cast provides the important information associated with patient to the dentists during diagnosis and treatment. However, the dental cast is fragile and difficult in storage, even very inconvenient in management. Computerization may provide a possible solution to the problem. In this study, the shape-from-shading technique is applied to reconstruct the dental cast into a 3D digital model. In general, this method has the problem of non-uniform light source. It is one of the major sources of error in 3D object reconstruction. For solving this problem, a LED matrix light is designed and used as light source to provide a uniform and stable illumination. Secondly, the light attenuation is also the error in shape reconstruction. An empirical calibration curve is obtained and implemented to improve model accuracy. Since the shape-from-shading technique can only be used to reconstruct the lighting view, the image registration and integration are developed to obtain a complete 3D model from several views using the brightness weighting method. Finally, by comparison of the reconstructed digital dental model and laser-scanned digital model, the error for the proposed system is significantly improved to be within the range from +0.57 mm to -0.95 mm.

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