1. A method for reconstructing image data on the basis of input projection data obtained via an X-ray computerized tomography system, wherein a target convolutional kernel is selected, which, when reconstructing image data from the input projection data using simple filtered back projection, would lead to target image characteristics, and wherein image data are then reconstructed using an iterative reconstruction method comprising: reconstructing image data of a first iterative stage from the input projection data; generating synthetic projection data on the basis of the image data of a current iterative stage; forming difference projection data on the basis of the input projection data and the synthetic projection data; generating residue image data from the difference projection data; combining the residue image data with the image data of the current iterative stage to form image data of an additional iterative stage, wherein the image data of the current iterative stage is subjected to filtering before or during combination with the residue image data by using a regularization convolutional kernel which is determined on the basis of the selected target convolutional kernel; and repeating the generating synthetic projection data, forming difference projection data, generating residue image data and combining until a termination condition occurs.