隨著台灣科技產業的發展，許多產品越做越小，例如微機電產品，或是奈米技術，都顯示出微小化產品已成為未來的發展趨勢。傳統接觸式三次元量床有其限制，較不適用於量測這種微小工件，因此發展出影像量測技術來解決此問題。 本研究之目的在建立一套影像對焦三次元量測系統，可運用於微小元件的尺寸輪廓量測。其中影像最佳對焦位置採用Sum-modified-Laplacian運算子計算影像之聚焦度量值，聚焦度量值成二次曲線分布，利用此種現象，配合數值分析，即能從少數幾張影像預測最佳對焦位置。 由本研究建立的影像對焦三次元量測系統量測待測工件外型尺寸，量測精確度在範圍0.7mm~15mm之尺寸的工件可達98%，量測之結果為點資料格式，可匯入電腦輔助設計繪圖軟體重建外型輪廓。 With the continuous development of scientific and technological industry in Taiwan, many products become smaller, such as micro-electro-mechanical’s products and nanotechnology’s components. All of those show the miniaturized will be the trend of future. Traditional CMM is not very well to measure those kinds of products, due to the limitation of probe’s diameter is too large to fit the size of work piece. For overcome the above mentioned problems, the optical measurement techniques have been developed recently. Image measurement technique is one kind of the optical measurement techniques, that using machine vision can achieve the full scale and real time measuring. Beside, this technique can avoid human’s misjudgment. It is also good for when the change of work piece’s surface is small than contact probe and any unwanted scratch on the work piece.
This study is using shape form focus method for micro-component’s dimensional measurement. The purpose of this research is to establish a non-contact image-measuring system. The image-measuring system utilizes a CCD camera with a fixed focal length. In this research, the Sum-Modified-Laplacian operator is utilized to compute local measures of the quality of image focus. The CCD camera is moved along the z direction, and so is the focus plane. The region, where the focus plane intersects the object, is the best focused area. The quadratic equations are used to model the result and calculate the focused measure values of sequential images captured by this system to obtain the most accurate depth estimates.
The accuracy of this non-contact image-measuring system can be achieved more than 98%. All the points after measurement can be transferred as IBL format, that means the result can be further reconstructed to three dimensional solid models by using CADCAM software.