影像式三維座標量測儀之研究

Abstract

本研究著眼於影像式座標量測儀操控系統的建立及量測性能的評估，影像座標量測儀主要包含機械結構，影像處理介面和馬達控制介面。座標量測儀包含一個兩個自由度的旋轉平台及一長度L的滑軌，影像處理介面以個人電腦為主，採用現成的影像擷取卡及CCD攝影機，運用影像處理的方法，來達到所需求的目的；馬達控制介面包含個人電腦、控制介面卡、馬達驅動電路、步進馬達及光編碼器（Encoder）。整個量測的工作原理說明如下，起先量測機台的工作座標為（0,0,0），當目標物已位於螢幕的中央時，即攝影機以對準目標物；將量測機台經由滑軌移至（L,0,0），使攝影機對準目標物，我們可以由CCD攝影機所轉動的馬達角度及滑軌長度L，利用三角定位來計算目標物座標。我們試著提出一個原理和機構都相當簡單空間座標量測技術，在運用影像處理理論和馬達控制的基礎下，發展一影像式的座標的量測系統，期望能以一個較簡單和低成本的量測設備來達到量測座標的目的。完成系統後，進行量測系統的評估，包含量測重現性、量測相對準確度及與臂式座標量測儀之比較，最後進行一量測應用。

In this thesis, we present the method of 3D measurement based on image technology. Our laboratory also developed a 3D measurement named as NCTU_CIDM 2000i which contains the mechanism, image process interface and motor controlling interface. The image process interface contains PC, image grabbing card and CCD camera. The motor controlling interface contains PC, stepping motor, control card, and encoder. We use triangulation to calculate the distance from origin to target. The theory of measurement as follows: First, the origin coordinate is (0, 0 , 0), when the target is located and shifted to the center of CCD image plane then moving the device to second position (L, 0, 0) and do the same thing. Finally, mechanism, image process interface and motor controlling interface are integrated as a computer program. And the repeatability error and relative accuracy error are evaluated. The comparison with robotic 3D measurement(MicroScribe 3D) on relative accuracy and repeatability is also evaluated.