Omnidirectional lenses for low cost laser scanners

Abstract

There is a need for small sensors that can provide 360° field of views in the intelligent vehicle applications. The usual technique has been to use a catadioptric system where a conical shaped mirror is placed in front of a camera, providing 360° horizontal field of view and in the order of tens of degrees of vertical view. The downside of these kinds of systems has been their size, usually ranging around 20 centimetres. A so-called omnidirectional lens can fold the optical path inside the lens decreasing the volume requirements considerably, while still providing comparative optical performance. In this work, two different omnidirectional lens systems are presented, the more common type of this lens images a whole surrounding scenery to an image sensor, providing instant 360° field of view. The other lens can select a known position from the 360° scenery, and provide an undistorted image of it. The other application for this type of lens is a laser scanner that necessitates direction selectivity. © Springer-Verlag Berlin Heidelberg 2011.