A method for generating a modulation tube current waveform acquires reflectance images of a subject and generates a surface contour characterization of the subject according to the reflectance images. The surface contour is registered to the imaged field of view. A volume image is formed according to the generated surface contour. A modulation factor for the radiographic volume imaging apparatus is determined at a plurality of modulation points. A modulation tube current waveform is generated using the modulation factor.