1. A method, comprising: initializing, by one or more computing devices, a reconstruction of camera motion and camera intrinsic parameters for an image sequence including a plurality of frames, wherein said initializing the reconstruction comprises: obtaining a set of point trajectories for the image sequence; determining a subset of the plurality of frames as keyframes in the image sequence; selecting a pair of the keyframes as initial keyframes for the image sequence according to the set of point trajectories; and generating an initial reconstruction of camera motion and camera intrinsic parameters for the image sequence according to the pair of initial keyframes and at least a portion of the set of point trajectories, wherein the initial reconstruction covers a portion of the image sequence.