The invention discloses a real-time
video camera tracking method based on key frames, which comprises the following steps: (1) capturing an index
image sequence, and restoring a sparse three-dimensional
characteristic point structure of a scene by a method of inferring a structure from movement; (2) giving the index
image sequence and the sparse three-dimensional
characteristic point structure, and automatically selecting the key frames by optimizing an energy function related to the key frames; (3) in the real-time
video camera tracking process, for each frame of real-time input image, firstly, quickly positioning a
candidate key frame similar to the real-time input image from the
key frame set by a characteristic word tree method of image recognition; and (4) matching the characteristic points abstracted on the real-time input image with the characteristic points on the
candidate key frame, obtaining the corresponding three dimensional coordinates of the characteristic points on the image, and calculating the directionality parameters of the
video camera. The invention has high calculating efficiency and stable solving result, and the video
camera tracking result obtained by the method can be directly used for the applications of reality enhancement,
virtual interaction and the like.