本論文致力於設計出一套形狀記憶合金驅動的自動對焦系統，主要分為硬體架設與軟體開發兩部分。對焦致動器機構採用線型態的形狀記憶合金驅動致動器做往復運動，搭配光學成像原理，挑選適當的鏡片與感光元件，架設出成像平台。並設計PWM電流加熱電路，控制記憶合金線的溫度。透過微控制器作為軟硬體間通訊的橋樑，將電腦端判斷求得的加熱電流值傳送至硬體電路。在電腦傳寫Borland C++ Builder人機介面，即時截取Web Camera的畫面，利用影像識別畫面的清晰程度，作為被動式對焦演算法中的性能指標，運用爬山法的概念設計出電流調變的法則。本文中設計幾種調變法則，藉由些特性參數來比較，哪種為較佳的調變方法。最後，將整套可以實際運作的自動對焦流程，移植到ARM嵌入式系統，期望能脫離電腦的控制，精簡整套對焦系統。This thesis is dedicated to design the auto focus system driven by the shape memory alloy, mainly divided into two parts of the hardware setup and the software development. The focus actuator uses the line type of the shape memory alloy to drive the mechanism doing the reciprocating movement. Then, with the optical imaging principle select the appropriate lens and the image sensor to set up the imaging platform. And designing the PWM circuit controls the shape memory alloy temperature. Through the microcontroller as the communication sends the message calculated on the PC to the heating circuit.In the computer, writing the Borland C++ Builder interface captures the real time image from the web camera, and identifies the image clarity. Using the mountain climbing search concept designs the several current modulation rules. Which will be compared the advantages and disadvantages from the real experiment result.Finally, the whole working auto focus processes are ported to the ARM embedded system. Expect to break away the computer control to simplify the entire auto focus system.
