1. A method for calibrating an imaging apparatus for teeth comprising: (a) obtaining a spectral measurement from at least one light source; (b) obtaining a spectral measurement from a fluorescent emission generated from a tooth in response to said at least one light source; (c) measuring the spectral response of a camera; and (d) generating scalar multiplier values to be used in image processing, according to the spectral measurements made in steps (a), (b), and (c).