Cata-Fisheye Camera for Panoramic Imaging

We present a novel panoramic imaging system which uses a curved mirror as a simple optical attachment to a fish- eye lens. When compared to existing panoramic cameras, our "'cata-fisheye" camera has a simple, compact and inexpensive design, and yet yields high optical performance. It captures the desired panoramic field of view in two parts. The upper part is obtained directly by the fisheye lens and the lower part after reflection by the curved mirror. These two parts of the field of view have a small overlap that is used to stitch them into a single seamless panorama. The cata-fisheye concept allows us to design cameras with a wide range of fields of view by simply varying the parameters and position of the curved mirror. We provide an automatic method for the one-time calibration needed to stitch the two parts of the panoramic field of view. We have done a complete performance evaluation of our concept with respect to (i) the optical quality of the captured images, (ii) the working range of the camera over which the parallax is negligible, and (iii) the spatial resolution of the computed panorama. Finally, we have built a prototype cata-fisheye video camera with a spherical mirror that can capture high resolution panoramic images (3600times550pixels) with a 360deg (horizontal) x 55deg (vertical) field of view.