手機相機之光學影像穩定器設計

Abstract

近年來，在相機畫素的要求越來越高，手機體積的要求也越來越小的趨勢之下，朝向高畫素、小型化與輕薄化發展已成為時下重要課題。且因為隨身攜帶操作，使得防手振功能成為值得研究的主題。本論文旨在設計能抑制因手部振動造成的影像模糊的光學影像穩定器，由於空間有限，故本防手振系統主要採用浮動光學感測器的方式，實現不需防手振專用鏡頭，亦能達成小型化的防手振功能。本研究對於穩定器使用兩種控制法則，其一是順滑模態控制方法，另一種是以模糊控制為基礎之順滑模態控制，並利用霍爾效應感測器來測量位移量，以抑制手振所造成的影像模糊，且透過電腦下達指令給伺服馬達，以供給防手振裝置合理的振動量，並利用加速規測量其加速度。模擬與實驗結果，防手振系統之兩軸均能在200毫秒之時間內獨立完成目標定位之控制，以達到補償效果。而且使用以模糊控制之順滑模態控制方法的結果比順滑模態控制的結果為佳。

Recently, not only digital cameras but also mobile phones demand higher resolution and smaller dimension. It is essential to achieve high quality of image. In addition, because of portable usage, anti-shake requirement has become a research topic worth studying. This study aims at designing an optical image stabilizer (OIS) to suppress image blur caused by hand jitter when taking photos. Because of limited space, the anti-shake system adopts an image sensor of floating type. It not only does not need a special purpose lens for anti-shake but also can reduce the volume of the anti-shake system. To suppress image blur caused by hand jitter, this study uses sliding mode control and sliding mode approach to fuzzy control for the OIS system, respectively. Two Hall-Effect sensors are used to detect the displacement in dual orthogonal. A servo motor acts as a vibration source with arc displacement back and forth in experimental verification. Furthermore, the vibration acceleration of the OIS system is detected by an accelerometer. Simulation and experimental results show hand jitter compensation is achieved. Dual axes of OIS system can independently achieve precise position control within two hundred milliseconds. Moreover, experimental results using sliding mode approach to fuzzy control are better than those using sliding mode control.