隨著科技的發展，各項產品及設備中所使用的光學元件如反射鏡、各類型的透鏡、稜鏡、分光鏡…等等均被廣泛的使用，而光學元件的品質會直接影響一個光學系統的好壞，因此檢驗光學元件的技術就顯得相當的重要。
本文以掃描式白光干涉技術配合包絡法掃瞄並紀錄干涉訊號的強度，並透過數學計算將干涉強度轉換成相位資訊，再以目前常見檢測技術中非接觸式的子孔徑相位拼接技術，將光學元件的表面予以還原，在過程中，為了要量測多個區域的相位資訊，需要移動被測元件的位置，而此一步驟會導致干涉訊號消失，需要手動調整，不過調整的過程中無法精確的調整到干涉訊號最強的位置，這樣可能會導致掃描後所還原的相位資訊產生誤差甚至是遺失。
因此，本研究引入被動式自動對焦演算法，以邊緣檢測的數學運算為基底，搭配垂直移動之電控平台，紀錄影像強度後計算對焦值，並自動尋找出干涉訊號明顯的位置。在比較量測透鏡LA-1708的數據後，由手動對焦計算出的曲率半徑誤差為2.79%，自動對焦計算出的曲率半徑之誤差減少為1.45%，可以有效的減少人為調整所產生的誤差情形。

With the development of technology, optical components such as mirrors, various types of lenses, prisms, beam-splitters, etc. are widely used in various products and equipment, and the quality of optical components directly affects the quality of an optical system. Therefore, the technology for testing optical components is quite important.
In this paper, scanning white light interference technology is used to scan and record the intensity of the interference signal, and the interference intensity is converted into phase information through mathematical calculation. Then, the subaperture phase stitching technology is used to optical. The surface of the component is restored. In the process, in order to measure the phase information of multiple regions, the position of the component to be tested needs to be moved, and this step will cause the interference signal to disappear, which requires manual adjustment, but the adjustment process cannot be accurate. The adjustment may cause errors or even loss of phase information restored after scanning.
Therefore, this study introduces a passive autofocus algorithm, based on the mathematical operation of edge detection, with the electronic platform of vertical movement, records the image intensity, calculates the focus value, and automatically found. After comparing the data of the lens LA-1708, the curvature radius error calculated by manual focus is 2.79%, and the error of the radius of curvature calculated by autofocus reduced to 1.45%, which can effectively reduce the error caused by artificial adjustment.

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