1. A method of correcting a signal representation of a radiation image of an object comprising the steps of storing a matrix of correction values in a memory device, said correction values being obtained by read out of an image stored by a radiation detector that has been subjected to a flat field exposure, exposing said radiation detector to a radiation image of an object, generating for each pixel of said radiation image of said object a signal representation of the pixel value, characterised in that immediately following generation of said signal representation of a pixel value, the signal representation is applied to a processing unit, simultaneously a correction value pertaining to said pixel is read from said memory and applied to said processing unit, said signal representation is corrected by means of said correction value in said processing unit.