A telecentric imaging system is described comprising a Fresnel lens (2) mountable in proximity to an object (8) to be imaged, a source of light (12) for illuminating the object, and an aperture stop (6) located at least in vicinity of the back focal point of the Fresnel lens (2). There is also described an optical inspection machine incorporating the telecentric imaging system and a method for software correction of the optical distortion produced by the telecentric imaging system.