融入與互動式虛擬棒球遊戲中真人揮棒打擊

Abstract

本論文設計虛擬棒球遊戲中真人揮動手中真實球棒﹐打擊戴上頭盔顯示器 所看到的虛擬投來的立體棒球。主要的目的是希望在虛擬實境中引進計算 機視覺的理論和技術﹐配合基本的影像處理方法﹐實做出一個強調真人﹐ 真棒融入虛擬世界以及它們之間互動的遊戲效果。我們所使用的方法是﹐ 架設二台電視攝影機﹐事先進行攝影機調校的工作﹔使用者在二台電視攝 影機共同視野之內﹐由所戴立體頭盔顯示器以肉眼研判透過虛擬實境技巧 所產生的投球的球路﹐決定如何揮動手中球棒打擊﹐透過影像擷取卡﹐將 真人揮棒之影像資料分別由二台電視攝影機即時存入記憶體中﹐再經過簡 單迅速的影像處理﹐擷取出球棒上的特徵點﹐並計算出三維世界座標系統 的球棒位置﹔接著﹐將獲得的球棒位置經網路由影像處理平台傳送至另一 部虛擬實境的系統平台﹐與虛擬投出之棒球之瞬間立體位置做三維碰撞測 試﹔若擊中﹐藉由擊球點位置及打擊力道大小﹐算出棒球被擊中後之反彈 是高飛﹐平飛或滾地之判斷, 以及是界內或界外之估算。文中除對整個系 統之理論與實作描述外﹐並記載玩者實際參與遊戲之實驗過程。 The thesis is concerned with a virtual reality baseball system in which a real person can swing a real bat to hit the virtual baseball seen on the worn HMD(Head-Mounted Display). The main purpose is to bring in both the theory and technique of computer vision into virtual reality and, with the help of basic image processing skills, to design and implement a game. The game aims at emphasizing the real person, and real bat immersed in virtual world and the interaction between them.Our method uses two properly mounted TV cameras and carries out camera calibration. A user enters in the common view field of the two cameras, then judges how the baseball, generated by virtual reality skills and seen from the stereo HMD worn, is flying and decides how to swing the bat in his hands. Through two frame grabbers, we store the image data of the real person's swinging from the two respective TV cameras into the memory instantly.By means of simple and fast image processing techniques, we pick up the feature points of the bat, and calculate the bat position in 3D world coordinate system. Then we send the bat position from the image processing platform to the VR platform via network, and test its collision with the 3D virtual baseball at all instants. If hit, we estimate whether the ball is a fly ball, a line drive, or a ground ball? A fair or a foul? All these judgements are based on the striking force and position.The thesis not only describes the theory of the whole system and its implementation, but also reports the experiments about the user* s play in the actual game.