An X-ray imaging system for generating X-ray projections of an object, the X-ray imaging system including an X-ray device having a single X-ray source (110) for forming a plurality of X-ray beams (104), a filter (120) positioned within the plurality of X-ray beams, an object space where the object to be imaged is accommodated, and an X-ray detector (150) including an array of a plurality of pixels (151 . . . 155). The X-ray device, the filter, and the plurality of pixels are configured such that at least one pixel is exposed to the plurality of X-ray beams. X-ray radiation received by a particular pixel undergoes a same spectral filtration by the filter. Pixels receiving the X-ray radiation undergoing the same spectral filtration are summarized to a pixel subset.