Over the last decade, there has been an increasing interest in developing vision systems and technologies that support the operation of unmanned platforms for positioning, mapping, and navigation. Until very recently, these developments rely on images from standard CCD cameras with a single optical center and limited .eld of view, making them restrictive for some applications. Panoramic images have been explored extensively in recent years [12, 13, 15, 17, 18, 19]. The particular con.guration of interest to this investigation yields a conical view, which is most applicable for airborne and underwater platforms. Unlike a single catadioptric camera [2, 15], combination of conventional cameras may be used to generate images at much higher resolution [12].

In this paper, we derive complete mathematic models of projection and image motion equations for a down-look conical camera that may be installed on a mobile platform — e.g, an airborne or submersible system for terrain flyover imaging. We describe the calibration of a system comprising multiple cameras with overlapping fields of view to generate the conical view. We demonstrate with synthetic and real data that such images provide better accuracy in 3D visual motion estimation, which is the underlying issue in 3D positioning, navigation, mapping, image registration and photo-mosaicking.