An x-ray video image system has a CCD sensor used in the production of a video image from an x-ray image, with an optimum image quality being achieved with a high read-out speed. A light source uniformly illuminates the CCD sensor before the production of an x-ray image. The outputs of the sensor from successively scanned image lines are supplied respectively to a main processing channel and to an adjustable measurement channel. By comparing the processed outputs of these two channels deviations of the image signal from predetermined values are identified. Components in the measurement channel are then adjusted until the deviations are substantially eliminated. Black level matching, white level matching, and linearity matching between the two channels can be accomplished.