直接操作顯示於螢幕上的資料能為使用者帶來直覺且方便的使用經驗，因此近年來觸控螢幕已成為顯示科技的一個發展趨勢，其中多點式觸控技術更是受到相當大的關注。本研究提出一個使用雙攝影機為基礎的雙點式觸控螢幕架構與觸碰物偵測和定位的演算法，並透過觸控點追蹤以解決真假點問題，達成雙點觸控的功能。此方法可使一般市售之液晶螢幕外掛此一雙攝影機模組即可具有雙點式觸控的功能，而無須藉助特製的面板。相較於目前的多點式觸控技術，本方法有著成本低和體積小的優點。
　　此外，我們定義一組觸控手勢，並將其映射至滑鼠操作的控制指令，使之可以用來操控為滑鼠所設計的應用軟體。我們還規畫了觸控偵測程式和觸控軟體之間的觸資料傳輸協定。藉此，我們實現一個使用雙點輸入手勢操作的觸控軟體。
　　最後我們分別在19吋和42吋的螢幕上實作出雙點式觸控系統，再進行不同的應用軟體的觸控操作測試，以驗證此一觸控方法的可行性。此外，我們以點擊遊戲實驗來評估觸控系統可用性和效能，實驗結果顯示所提出的觸控方法具有良好的效能。

To touch and manipulate data on screens directly without any intermediary device provides more convenient and instinctive using experience to the user. Therefore, the touch screen has become a trend for the display technology in recent years, especially to multi-touch technique attracts more focus. In this work, we propose a vision-base touch screen architecture with dual cameras, touch detection and locating algorithms. For the fraud point problem, we adopt touch point tracking to solve it and achieve the dual touch ability. The ready-made liquid crystal display (LCD) can mount this dual cameras module to equip the dual touch ability, and the cost is cheaper and the volume is smaller than current multi-touch techniques.
Moreover, we define a set of touch gestures and map it to the controlling commands of mouse. This makes it can manipulate those application software designed for mouse. We also define a touch data transmission protocol between the touch detecting programs and touch software. By using above schemes, we realize the touch software which manipulated with dual touch point inputs.
Finally, we implement the dual touch system on the 19-inch and 42-inch displays, respectively. Then, to verify the feasibility of proposed method, we test the touch operations with various applications. Furthermore, we evaluate the usability of our system with a hit game experiment, and the result shows the proposed method provides a satisfying performance.

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