1. A method for improving the quality of computed tomography image series, comprising: scanning an examination object over a period of time which permits an acquisition of at least two temporally offset projection data records of an identical recording region; generating at least two temporally offset tomographic image data records, each including a multiplicity of pixels, by reconstructing the projection data records; transforming the image data records into transformation data records of at least two spatial frequency ranges; calculating temporal fitted values of the transformation data records for some of the spatial frequency ranges, and replacing the values of the transformation data records fitted by the calculated fitted values; performing an inverse transform of the transformation data records with the fitted values to form new image data records; and displaying the new image data records.