垂直移動式單CCD光學3D座標量測系統的研究

The Study of an Optical 3D Coordinates Measurement System with a Vertical Moving CCD

劉咨貝(Tzu-Pei Liu)

指導教授 ： 戴兢志

大同大學/工程學院/機械工程學系所/碩士(2009年)

摘要

本研究以針孔攝影原理為基礎，提出修正式相似三角形演算法建立一套垂直移動式單CCD光學量測系統，在CCD焦距允許的景深範圍內，設定鏡頭的兩個高度位置，並測量二個位置所對應的視野範疇值，以及擷取二個位置所對應的待測物影像資料，透過修正式相似三角形演算法即可求得特測物測量點的空間座標值。修正式相似三角形演算法是以簡單的線性方程式進行計算，優於一般量測系統較需要複雜座標轉換以及非線性計算。
本研究自製一個具有量測精度在0.5mm的簡單量具，可以同時用來測量CCD的視野範疇與景深，並可以計算CCD的焦距值。本研究探討環狀光源、待測物大小、測量點影像座標搜尋法與影像擷取卡輸出圖像解析度等因素對提升量測精度的影響，由實驗結果顯示除了環狀光源可以提升量測精度外，影像擷取卡所輸出圖像解析度的提升是提高量測精度的最主要因素。

關鍵字

光學量測系統 ； 單CCD ； 空間座標量測 ； 針孔成像系統

並列摘要

In this research, a revised similar triangle algorithm based upon the pinhole imaging principle was proposed to establish a 3D optical measurement system with a vertical moving CCD. Within the range of depth of field that allows for CCD’s focus length, set up two altitude positions of the lens. Measure the values of view of field and acquire image data of measured objects corresponding two altitude positions of the lens. The space coordinates that specially examined the measuring point of objects can be obtained through the revised similar triangle algorithm. The revised similar triangle algorithm is based upon simple linear equations system. It is superior to general systems that need relatively complicated coordinate transformations and non-linear calculations.
This research makes a simple measuring tool with a 0.5-mm precision to measure the values of view of field and depth of field at the same time. These values can be implemented to calculate the focus length of CCD. This research probes into the ring light source, the size of measured object, the search law for image coordinates and the resolution of image capture board to analyze influence on the improvement for measuring accuracy. The experimental results reveal that the resolution of image capture board is a main factor which improves the precision of measurement, except the ring light source.

並列關鍵字

Single CCD ； Pinhole imaging principle ； Optical measurement system ； Space coordinates measurement

參考文獻

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