1. A digital image acquisition device, comprising an image acquisition sensor, a shutter, optical elements for focusing an image on the sensor, an aperture disposed between said optical elements and said shutter, a translucent lens cap which defocuses images when in place, and digitally-embedded programming such that the device is arranged to automatically capture a calibration image of a de-focused scene when said shutter and said aperture are open, and to derive a map of defects from the calibration image acquired by the sensor when illuminated by ambient light, the digitally-embedded programming capable of classifying defects and determining if the digital image acquisition device is acceptable for use.