臺灣博碩士論文加值系統

在視覺系統中，攝影機取得的是二維平面之影像，其與三度空間實物之幾何關係，尚差一個深度(depth)資料。如能利用相關技術取得深度(Z)之資訊，再加上二維平面的點資料(x,y)，即可繪出三度空間之立體圖，或應用於逆向工程中三維重建技術。
本研究中我們以兩台攝影機與一台投影機建立了一套非接觸式光學系統，電腦產生多頻率弦波條紋圖案投射到物體表面並以兩台攝影機拍攝。用四步相移法配合多頻率結構光進行相位展開，有了物體表面上之絕對相位，對應攝影機畫素座標，便可知道二維平面的點資料(x,y)所對應之待測物三維座標，點資料與三維座標可連成一經過攝影機原點之直線方程。待測物上之絕對相位可得知其投影光平面方程，計算投影光平面方程與直線方程之交點，即可得知其三維座標點。
在計算其交點前，還需做攝影機與投影機校正。以內部與外部參數做座標系轉換，失真參數校正其失真影像。系統亮度線性校正為重要之一環，若投影機輸出亮度與攝影機擷取亮度為非線性，計算絕對相位時會有誤差。

In the visual system, two-dimensional image is obtain by camera. But it still lack depth information between image and object. If it can get depth (Z) information and point data (x, y) of two-dimensional plane. Then can draw three-dimensional picture to apply in reverse engineering three-dimensional reconstruction.
In this study, we build a non-contact optical system by two cameras and a projector. Produce multi-period structured light by computer, then projected onto the object and captured by two cameras. Phase unwrapping based on four-step phase-shifting and multi-period structured light. If got absolute phase, corresponding the absolute phase of the object and camera pixel coordinates. Will know the relationship between point data (x, y) and three-dimensional coordinates. Connected three-dimensional coordinate and point data can be a linear equation passing through the origin of the camera. It can find the projected light plane equation by absolute phase. Calculating the intersection point of the projected light plane equation and the linear equation is the three-dimensional coordinate.
The camera and the projector need to calibration before calculating the intersection point. Coordinate system transformation by internal and external parameters. Undistorted image by distortion parameters. Calibration the linear brightness system is one of important. If the projector output brightness and the camera input brightness is nonlinear, when calculating the absolute phase will error.

誌謝 i
摘要 ii
Abstract iii
誌謝 v
圖目錄 ix
表目錄 xii
第一章 緒論 1
1.1 前言 1
1.2 研究動機 1
1.3 研究方法 3
1.4 文獻回顧 3
1.5 論文架構 7
第二章 量測原理 8
2.1 量測原理概述 8
2.2 結構光(structured light) 9
2.2.1 相位移法(phase-shifting) 10
2.3 相位展開 13
2.4 三維輪廓量測常見方法 16
2.4.1 飛行時間法 17
2.4.2 干涉法 17
2.4.3 疊紋法 17
2.4.4 三角測量法 18
2.4.5 雙目視覺法 20
2.5 投影光平面與攝影機射線交點 24
第三章 攝影機與投影機校正 27
3.1 攝影機校正 27
3.2 攝影機模型 28
3.2.1 內部參數 29
3.2.2 外部參數 31
3.2.3 透視投影 32
3.2.4 鏡頭失真 33
3.3 投影機校正 35
3.3.1 投影方式 36
3.3.2 利用局部座標與最小平方法計算絕對相位 37
3.3.3 絕對相位轉換像素座標 39
3.4 系統亮度線性校正 41
3.5 數位影像之雜訊濾除 44
第四章 實驗架設與結果 46
4.1 實驗系統介紹 46
4.2實驗步驟與結果 48
4.2.1 投影機校正步驟與結果 48
4.2.2 攝影機校正步驟與結果 53
4.2.3 量測步驟與結果 56
4.2.4 空間網格點驗證三維座標 64
第五章 結論與未來展望 65
參考文獻 67

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