1. A method for processing images to detect dental caries, said method comprising: directing incident light toward a tooth, wherein said incident light excites a fluorescent emission from tissue of said tooth; obtaining a fluorescence image from said fluorescent emission; obtaining, from reflected light, a reflectance image of said tooth tissue; and using a computer to: applying color balance to said reflectance image to compensate for variation in exposure of the tooth to the incident light to produce a color balanced reflectance image of the tooth; removing specular reflectance from said color balanced reflectance image while leaving back-scattered reflectance, to produce a specular reflectance corrected image of the tooth, said removing comprising: identifying pixels in said color balanced reflectance image, said identified pixels having values above a signal threshold and being associated with specular reflectance regions; removing specular reflectance regions from said identified pixels; identifying regions surrounding said specular reflectance regions; averaging pixel values in said color balanced reflectance image in said surrounding regions; and replacing said specular reflectance regions in said color balanced reflectance image with a signal value including said averaged pixel values; registering said fluorescence image with said specular reflectance corrected image; and combining said registered fluorescence image with said specular reflectance corrected image to provide a diagnostic image for detecting dental caries.