1. A method for processing X-ray data to determine an identity of an object under inspection, comprising: a. Transmitting a plurality of X-rays, wherein said X-rays have a range of energies, through the object; b. Detecting said transmitted X-rays at a detector array, wherein each detector in said detector array outputs a signal proportional to an amount of energy deposited at said detector by a detected X-ray; c. Reconstructing an image from said signal, wherein each pixel within the image represents an associated mass attenuation coefficient of the object under inspection at a specific point in space and for a specific energy level; d. Fitting each of said pixels to a function to determine the mass attenuation coefficient of the object under inspection at the point in space; and e. Using said function to determine the identity of the object under inspection.