被動式自動對焦機制之研究

A Study of Passive Auto-Focus

許峻瑋(Chun-Wei Hsu)

指導教授 ： 李朱慧

朝陽科技大學/資訊學院/資訊管理系/碩士(2011年)

摘要

隨著數位技術的應用與發展，加上數位相機的操作變得很容易，因此數位相機比一般電子產品更受所有年齡層所歡迎；而數位相機在靜態影像拍攝和視訊拍攝上，對焦系統是很重要的功能。一般而言，對焦系統是利用聚焦感測器測量焦距，而本研究中，我們提出了一個新的被動式自動對焦機制，是使用影像感測器直接測量和評估影像的焦距，而影像經由電荷耦合元件(Charge Coupled Device, CCD)或互補金屬氧化物半導體(Complementary Metal-Oxide-Semiconductor, CMOS)影像感測器產生之後，讓使用者選取感興趣的區域(Region of Interest, ROI)之影像，系統將自動找出該ROI的最佳對焦位置，讓對焦機制更加精確且具有彈性。

本研究中提出二種被動式自動對焦機制，稱為DCT-STD與DCT-STD-Subregion，研究中將以實驗驗証所提的機制優於現有方法。

關鍵字

標準差 ； 自動對焦 ； 數位相機 ； 離散餘弦轉換 ； 感興趣的區域

並列摘要

With the development and application of digital technologies, the digital camera is more popular than other electronic products for all ages. The operations of digital cameras are facile and the user interface is similar in most brands. Auto-focusing is a common but important feature both for still image photography and video photography. Traditionally, focusing sensors are utilized for auto-focusing systems; in this study, we propose a new auto-focusing mechanism which uses the image sensor directly for measuring and estimating the focal distance. After the image is captured by Charge Coupled Device (CCD) or Complementary Metal-Oxide-Semiconductor (CMOS) image sensors, users will select Region of Interest (ROI) and the system can explore the in-focus image automatically.

This research proposed two new passive auto-focus mechanism, named DCT-STD and DCT-STD-Subregion. Experimental results showed they are better than previous works.

並列關鍵字

Auto-focusing ； Digital Camera ； Discrete Cosine Transform ； Region of Interesting ； Standard Deviation

參考文獻

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