雙攝影機數位條紋投影技術應用於人類牙齒三維形貌量測

3-D shape measurements of human tooth by using dual-camera digital fringe projection techniques

鄧力瑋(Li-Wei Teng)

指導教授 ： 陳冠辰

共同指導教授 ： 劉承揚(Cheng-Yang Liu)

淡江大學/工學院/機械與機電工程學系碩士班/碩士(2019年)

https://doi.org/10.6846/TKU.2019.00023

摘要

本論文成功建立出一套雙攝影機數位相位移量測系統，用以量測各式牙齒之三維輪廓，如3D列印牙齒、牙齒石膏模型以及真實人類牙齒，結合數位結構光投影技術、七步相位移法、相位展開技術、參考平面扣除法、二值化來進行量測與影像處理運算，並運用透視變換以及影像影像座標與空間平面座標轉換將影像座標轉為物體所在平面座標，並將原影像相位值轉換至原物體所在之平面，改善原本因拍攝角度相位的誤差。在系統方面，使用數位投影機作結構光源，投影出黑白餘弦結構光，攝影機作為影像擷取裝置，擷取圖像回傳至電腦進行計算。於實驗結果比較15、25、35與45度共四種角度的量測效果，其中以15度量測效果最佳，並比較週期0.95 mm與週期1.9 mm黑白餘弦條紋對於各種牙齒形狀的量測效果，以週期1.9 mm的黑白餘弦條紋效果最佳。本量測系統量測精度可達17.5 "μm" ，可用於進行牙模工程檢測與牙醫診斷，提升牙模效率和品質與醫師診斷之正確性。

關鍵字

三維曲面量測 ； 結構光 ； 相位移技術 ； 牙齒量測

並列摘要

In this thesis, a dual-camera digital fringe projection system is used to measure various kinds of tooth 3D profilometry, such as 3D printed tooth, Plaster tooth mold and Human tooth. The system integrated digital structured light projection, seven-step phase-shifting, phase unwrapping, reference plane subtraction and binarization. The algorithms transfer the image phase onto the plate which the object is located by using perspective transformation, image and spatial coordinate transformation. It reduces the phase error due to detecting angle. In the experimental system, a DLP projector is used to project black-and-white cosine fringe pattern onto tooth surface and two CMOS cameras are used to capture image and transmit data to computer for calculation. Four detecting angles (15° , 25° , 35° and 45° ) and two period of structure light (0.95 mm and 1.95 mm) are used in the experiment. Detecting angle of 15° and structured light period of 1.95 mm show the best result. The resolution of this measurement system reach 17.5 μm, and can be applied to plaster tooth mold detection to improve quality, efficiency, and accuracy of dental diagnosis.

並列關鍵字

Three-dimensional surface measurement ； Digital structured light ； Phase-shifting method ； Tooth measurement

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