In various x-ray imaging methods, including scattering correction and phase contrast imaging, intensity modulation in space is introduced into the projection images by the use of masks, gratings, or apertures. The present invention relates to a process to demodulate the modulation. The current demodulation processes are either to remove the modulation pattern through digital processing or to move the modulation pattern on the detector in a series of images that requires mechanical movements of a component and tends to lose some information of the imaged object. The demodulation of the present invention can be realized with a relative movement between the projected image of the sample and the modulation pattern without having to move the modulation pattern. The demodulated images are free of the modulation pattern and have better clarity.