The illumination apparatus and methods described herein increase the depth of the illuminations tissue penetration, help minimize surface reflections and back-scatter for a non-contact camera based imaging system thus providing increased tissue-structure contrast and more information about the structures beneath the surface. It does this by using one or more of the following techniques:using optics to provide radiation which hits the surface at or near 90 degrees for better tissue penetrationusing optics and radiation source placement to control the angular distribution of light from surface vertical to minimize surface specular reflection and subsurface reflectionremoving some surface light reflection through patterning the intensity of the light source thus increasing contrast in areas of no or low direct irradiationsynchronously with respect to camera frames or through user selection, switching on and off light sources which has the effect of 1) dynamically changing the overall angular distribution of light thus changing surface level reflectance 2) revealing and through processing removing unwanted patterning caused by optical defects or contaminants on optical surfaces or surface hair 3) moving illumination patterns to permit contrast enhancement in all areas of the surface.
