1. A computer-assisted method for aligning two digitized overlapping hemispheric images of an environment obtained with a fisheye lens comprising the steps of (a) receiving the location of three spatial points as recorded in the overlapping region of each hemispheric images; (b) determining the translation and rotation of one hemispheric image relative to its ideal position from the locations of the three spatial points in the two images based on a displacement model; and (c) obtaining the centre of projection in each image.