在齒顎矯正上，牙醫師可從各種不同的資訊進行病患的齒顎功能分析，在這些資訊之中，石膏牙齒模型提供牙醫師病患牙齒咬合以及立體的牙齒距離資訊，此外，牙醫師也可在牙齒模型上進行手術模擬，因此，牙模的確扮演齒顎矯正上不可或缺的重要角色，但是，因為石膏牙模易碎的材料特性及佔空間的缺點，使得保存實體牙模成為牙醫師的困擾。雖然將牙模數位化可解決此問題，但是使用目前常用的雷射掃描器或是電腦斷層來進行牙模數位化又過於昂貴。因此，本研究使用實驗室過去發展的陰影造形法來達到數位牙模的目的，此外，為了得到較為精確的數位牙模，每次重建僅重建部份牙模，再使用薄板鍵影像對位法來得到完整的數位牙齒模型，薄板鍵影像對位法可允許對位物體依照特徵點進行形變，因此可達到彌補重建數位牙模誤差的優點，為了提供一個適合陰影造形法的環境，本研究設計一套適合拍攝影像的系統，並利用數位編碼器計算物體與鏡頭間的距離，以期減少量測距離上的誤差，最後，我們將研究成果與雷射掃描結果進行比較以評估本系統的效能，在部份虛擬牙模重建誤差分布在0.5mm~-0.5mm，而合併後的整體虛擬牙模重建誤差分布在1.09mm~-1.09mm間。

　　In the orthodontics, dentists can analyze the functions of teeth and palate from different materials. In these materials, dentists obtain the three dimensional information about bite information and distance between teeth from gypsum dental cast. Besides, dentists also can simulate the orthodontics on the casts. Hence, the dental cast plays an important role on the orthodontics. Because the fragile property of gypsum dental cast and disadvantages of occupying space, these reasons persecute with dentists. Although these problems can be solved by digitizing dental cast, it costs a lot by using laser scanner or computed tomography. Hence, the Shape from Shading method that is developed in our lab past is applied to reconstruct shape of dental cast. Besides, the dental cast is reconstructed partiality every time for obtaining more accuracy virtual result. Then the Thin Plate Splines method is applied to register every part of dental cast to a whole model. The advantage of this method is that permits the matching object to do elastic deformation and retrieve the error of reconstructed. A suitable capturing images system is developed for Shape from shading. And rotated decoders are applied to measure distance between object and CCD camera in this system. We hope that can reduce the error of measurement. Finally, the study result is compared with result that is obtained from laser scanner to estimate the effect of our system. The reconstructed error of partial virtual dental cast is spread from 0.5 mm to -0.5 mm. The reconstructed error of integrated virtual dental cast is spread from 1.09 mm to -1.09 mm.

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