條紋投影三維取像與校正及其360度建模之研究

Abstract

本論文主要探討條紋投影量測技術(Fringe Projection Profilometry)及其重建資訊的校正，以達到建立真實完整三維模型的目的。本文從討論條紋投影之應用領域作為出發，接著探討系統理論上之運作方式，依序介紹三角重建理論、弦波條紋相位擷取與相位展開。而隨著理論上與實際應用之差異性引入校正程序之介紹，從縱向深度校正開始，以多項式擬合方式建立「相位-縱深關係式」，將之應用於條紋相位提升深度量測精準度，接著使用相機校正的方式建構量測系統之立體座標空間，並將拍攝到之影像Pixel Index進行橫向校正，使得每一個像素點皆可映射為空間中之實際之座標點，達到建立量測結果三維座標值之目標，並達成50um之縱向準度與150um之橫向準度。完成單面量測之後，對於一個實際之完整物體可以進行完整三維模型之建立，以旋轉之方式對每個角度進行量測之後，經由校正旋轉軸方向與位置之方式來對單面進行旋轉以拼合為完整之360度立體模型，並在文末給出了實驗系統之精準度等數值與實際建立模型之範例。This work aims on the calibration procedure of fringe projection profilometry and the reconstruction of a 3D profile model. To establish the relationship between the theoretical FPP technique and the practical measurement, the calibration procedure is used to transfer the measured metrics to the real world coordinates. First, the depth information taken from the FPP system is calibrated by the “Phase to Depth Equation”. Second, the technique of camera calibration is adopted to construct the 3D coordinate system of the measurement and the lateral coordinate of the measured results. Finally, the calibration of the revolution axis is carried out for the reconstruction of the whole shape 360 degree model. System parameters and an example are attached at the end of this work. After the calibration procedure, we can establish the accuracy of 40 um in vertical and 150 um in lateral around the 20*20*16 cubic centimeter measurement range.