A method for correcting an X-ray diffraction (XRD) profile measured by an X-ray diffraction imaging (XDi) system is provided. The XDi system includes an anode, a detector, and a control system. The method includes obtaining an emission spectrum of the anode using the control system. The emission spectrum includes spectral structures. The method further includes calculating a piecewise spectral-correction function using the spectral structures in the emission spectrum, obtaining a measured spectrum of an object, and applying the spectral-correction function to the measured spectrum to generate a spectrally-corrected measured spectrum.