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 based on the detector signals, and with a modular conveyor chain comprising identical modular segments that are hinged together in a closed loop, serving to transport articles under inspection through a space that is traversed by the scanning rays, said method serving to remove from the radiographic image a background image that is caused essentially by the conveyor chain 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 detector array by measuring their respective diode currents while the radiation source is turned off and retaining said digital calibration data in a one-dimensional data array, C2) acquiring raw image data for one of the modular segments including adjacent border portions of the immediately preceding and the next following modular segment 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) into normalized calibration data which are referenced to at least one clearly definable feature that occurs identically in the radiographic image of each of the modular segments and storing said normalized calibration data in a calibration data file as a digital template image, and 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 a section of the conveyor chain with at least one article travelling on it 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 said section of the conveyor chain, I2) arithmetically processing the raw digital image into a normalized digital image which is referenced to said at least one clearly definable feature and retaining the normalized digital image of the article with the background of the section of the conveyor chain in a two-dimensional data array, and I3) removing the background of the conveyor chain from the normalized digital image by applying to the latter a correction corresponding to the digital template image. C1) acquiring digital calibration data through determination of the dark signals of the individual photodiodes of the detector array by measuring their respective diode currents while the radiation source is turned off and retaining said digital calibration data in a one-dimensional data array, C2) acquiring raw image data for one of the modular segments including adjacent border portions of the immediately preceding and the next following modular segment 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) into normalized calibration data which are referenced to at least one clearly definable feature that occurs identically in the radiographic image of each of the modular segments and storing said normalized calibration data in a calibration data file as a digital template image, I1) acquiring a radiographic image in the form of raw digital image data of a section of the conveyor chain with at least one article travelling on it 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 said section of the conveyor chain, I2) arithmetically processing the raw digital image into a normalized digital image which is referenced to said at least one clearly definable feature and retaining the normalized digital image of the article with the background of the section of the conveyor chain in a two-dimensional data array, and I3) removing the background of the conveyor chain from the normalized digital image by applying to the latter a correction corresponding to the digital template image.