A System for image processing, comprising an input interface (IN) for receiving energy resolved count data generated by a photon-counting detector (PCD) with at least 2 energy bin but preferable more than two. A count data transformer (DT) of the system is configured to perform a transformation operation to transform the energy resolved count data into transformed count data, the operation including applying one or more weights to the count data, the weights previously obtained based on i) calibration data for the or a photon-counting detector and ii) calibration data for an energy integrating detector.The system allows emulating an energy integrating detector.