Mosaic construction from a sparse set of views

This paper describes a flexible approach for mosaic construction from a sparse set of uncalibrated views. The observation, that in architectural environments the majority of lines is aligned with the principal orthogonal directions of the world coordinate frame, is exploited in different stages of the mosaic construction pipeline. In the first stage the vanishing points are automatically detected and used for partial calibration of the camera and estimation of camera's relative orientation with respect to the scene. This single view analysis enables efficient feature matching and alignment of multiple views. In the final mosaic construction stage the internal camera parameters are refined simultaneously using all available views. We point out some practical issues related to the conditioning of this self-calibration technique. While the approach described here can be presented in the context of rotational mosaics, the alignment and matching techniques are applicable for general displacements, where the constraints of man-made environments are present and the displacement between the views is large.