A method of operating a radiographic inspection system with a radiation source emitting scanning rays, further with a radiation detector receiving the scanning rays and converting them into detector signals, with a processor generating a radiographic image (31, 32, 33) based on the detector signals, and with a modular conveyor chain comprising identical modular segments that are connected in a closed loop, serving to transport articles under inspection through a space that is traversed by the scanning rays, wherein each modular segment comprises a registration feature; said method serving to remove from the radiographic image a background image that is caused essentially by the conveyor chain modular segments and by factors inherent in the radiation detector, wherein the method comprises a calibration mode with the steps of: C1) acquiring digital calibration data through determination of the dark signals of the individual photodiodes of the radiation detector array by measuring their respective diode currents while the radiation source is turned off, digitizing said diode current and retaining said digital calibration data in a one-dimensional data array, C2) acquiring raw image data for one of the modular segments of the empty conveyor and retaining the raw image data in a first two-dimensional data array as a raw digital image of the modular segment, C3) digitally processing the data retained in steps C1) and C2) reflecting the influence of the radiation source and the radiation detector and the image data for one of the modular segments into calibration data and storing said calibration data in a memory of the radiographic inspection system, wherein the method further comprises an inspection mode with the steps of: I1 acquiring a radiographic image in the form of raw digital image data of the articles travelling on the conveyor chain, and retaining the raw digital image data in a second two-dimensional data array as a raw digital image of the article with the background of the conveyor chain, and I2 arithmetically processing the raw digital image data with the help of the calibration data into a clear output image without said background image, and wherein the method further comprises referencing a location within any radiographic image to the underlying modular segment with a longitudinal registration coordinate (y) in a transport direction of the conveyor chain. C1) acquiring digital calibration data through determination of the dark signals of the individual photodiodes of the radiation detector array by measuring their respective diode currents while the radiation source is turned off, digitizing said diode current and retaining said digital calibration data in a one-dimensional data array, C2) acquiring raw image data for one of the modular segments of the empty conveyor and retaining the raw image data in a first two-dimensional data array as a raw digital image of the modular segment, C3) digitally processing the data retained in steps C1) and C2) reflecting the influence of the radiation source and the radiation detector and the image data for one of the modular segments into calibration data and storing said calibration data in a memory of the radiographic inspection system, I1 acquiring a radiographic image in the form of raw digital image data of the articles travelling on the conveyor chain, and retaining the raw digital image data in a second two-dimensional data array as a raw digital image of the article with the background of the conveyor chain, and I2 arithmetically processing the raw digital image data with the help of the calibration data into a clear output image without said background image,