A radial imaging system is provided for capturing an image of an object which extends radially around an image sensor in an object plane. A reflector (42) is used for reflecting incident light (46) to a generally axial direction. The image sensor (40) receives the generally axially directed reflected light, and it has a stepped reflector surface having a series of reflecting linear facets (48) which together form a generally curved, e.g. concave surface. This design enables improved uniformity of the imaging performance with respect to the radial distance to the object being imaged.