Different image-based applications may benefit from different imaging technologies. A popular example are omnidirectional cameras which, due to their large field of view, are extremely useful in robotics and videosurveillance. We will review these and other imaging technologies that go beyond usual cameras and explain motivations for using them. The core of the lecture will concern the geometric modelling of different imaging systems and its use for calibrating them and perform structure-from-motion computations such as motion estimation and 3D modelling.