1. A method for determining at least one of correction coefficients and parameters for detector channels for a computed tomograph, comprising: inserting a phantom with a smooth cross-sectional profile into the computed tomograph in such a way that at least two different attenuation values are detected in a scan, the phantom including a plurality of projections of virtually all the detector channels; carrying out at least one scan in order to obtain a sinogram of the phantom; subjecting attenuation profiles, obtained from the sinogram for each projection of the scan, to high-pass filtering in order to obtain discrepancies from an ideal profile which is predetermined by the phantom; and matching a model function, for each detector channel, to the discrepancies which are obtained for the detector channel, as a function of the detected attenuation values, from which the at least one of correction coefficients and parameters are obtained.