A method for the reconstruction of image data based upon a plurality of multi-energy projection measurement data sets of a field of examination of an object under examination is described. In an embodiment of the method, a plurality of projection measurement data sets, produced via multi-energy CT imaging using differing X-ray energy spectra of the field of examination of the object under examination, are captured. In addition, a reduced number of image data sets are produced based upon the plurality of projection measurement data sets by applying a basic material decomposition and an image mix. An image data reconstruction facility is also described. Furthermore a computed tomography system is described.