1. A system for capturing images of a scene using wide band illumination with known spectral distributions in the presence of ambient illumination having an unknown spectral distribution, comprising: a digital camera; and a wide band illumination source comprising, an illumination source with a known spectral distribution, and multiple filters, each having a known spectral transmittance distribution, wherein a different one of the filters is positioned in front of the illumination source for each image captured by the camera.