1. A ranging apparatus comprising: an illumination means for illuminating a scene with a projected two dimensional array of light spots; a detector for detecting the location of each of said spots in the scene; and a processor adapted to determine, from the detected location of said spots in the scene, the range to those spots, wherein the illumination means comprises a light source arranged to illuminate only part of the input face of a light guide, the light guide comprising a tube having substantially reflective sides and being arranged together with projection optics so as to project an array of distinct light spots towards the scene.