说明：  无标识物的增强现实，实时跟踪，具有一定的鲁棒性
(This paper addresses the problem of markerless real- time augmented reality (AR). Many different types of sen- sors have been used to achieve this including : GPS, gy- roscopes, cameras, hybrid vision, accelerometers and many more which have been summarized in [1, 2]. )