A system and method for generating multi-energy computed tomography images of a subject using a polychromatic x-ray source with single spectrum includes acquiring a measure of a polychromatic spectrum of a polychromatic x-ray beam generated by the polychromatic x-ray source. The method also includes acquiring attenuation data generated by operating the polychromatic x-ray source, segmenting the attenuation data based on a plurality of component criteria to create plurality of segmented datasets, and generating template data from the segmented datasets. Using the template data and the measure of the polychromatic spectrum, polychromatic synthetic data is generated. Using the template data and each of the segmented datasets, component synthetic data is generated. Using the attenuation data, the polychromatic synthetic data, and the component synthetic data, a plurality of multi-energy images, including separable images weighted for each of the component criteria, is reconstructed.
