擷取人體動作的動作資訊在電腦視覺或其他一些領域裡伴演很重要的角色，如虛擬實境、自動控制、人物識別等，尤其是目前正快速竄起的遊戲產業，必須大量使用Motion Capture取得遊戲中人物角色的所有動作；還有在拍攝數位電影方面，Motion Capture也佔有相當大的一個份量；可見，Motion Capture的使用已經越來越普遍了。但是，目前使用Motion Capture系統的成本非常昂貴，而且使用上不甚方便，常常需要穿戴一些特殊的裝置才能使用。所以，如果有一個簡單而且便宜的方式取得人體動作資訊，對於Motion Capture的推廣與使用會有很大的幫助。 Motion Capture的發展已經有多年的歷史了，早期研究以下列四種研究最多：(一)磁場式Motion Capture；(二)超音波式Motion Capture；(三)機械式Motion Capture；(四)光學式Motion Capture。單純透過影像來擷取人體動作資訊需要較多的運算時間，由於電腦的運算速度越來越快，因此近幾年有一些學校及研究單位開始研究以視訊影像輸入為主的Motion Capture系統。透過影像處理式Motion Capture，不但可以節省成本，而且使用上也比上述四種方式方便許多。有鑑於此，本論文提出了一個可以透過視訊影像取出人體動作資訊的方法，透過追蹤人體頭部與四肢的影像區域來取得人體的動作資訊，而且，本系統只使用了一個鏡頭，因此，成本與使用方便性上面都有較高的優勢。由實驗結果可以看出，我們提出的系統的確具有可行性與有效性。 The capturing of human motion plays a very important role in several computer vision applications, such as virtual reality, automatic control and posture recognition. In some game designation sites, designers need to capture human motions to obtain all actions of roles in the game. When directors want to film a 3D-animated movie, he might also use motion capture frequently. However, the equipments of motion capture are very expensive. Moreover, it is not easy to use these equipments. The actors must wear some devices, which results in the inconveniently of their actions. If there are some inexpensive and easy technologies to be employed to capture human motions, they can be soon applied in the real world. Researches of motion capture had been developed many years. They can be categories into four main groups, which are (1)magnetic motion capture, (2)ultrasonic motion capture, (3)mechanical motion capture, and (4)optical motion capture. Recently, some researchers in investigate image-based motion capture system. However, these methods are usually time-consuming. In this thesis, we develop a system that captures human motions from video sequences. Actors’ head and limbs are tracked and located directly from video sequences. Another characteristic of the proposed system is that it only uses one camera to capture the video. In the way, the cost can be reduced computing with other systems. Experimental results demonstrate the feasibility and validity of the proposed system.
