Abstract: An x-ray diagnostics installation has an x-ray source, an x-ray image intensifier video chain, and a control circuit connected to the output of the video chain which includes a circuit for data reduction which combines a number of image points of the total x-ray image into smaller image regions. A threshold circuit for contour recognition is connected to the output of the reduction circuit, which compares the measured values of the individual image regions to a threshold, and transmits through only those measured signals corresponding to darker regions of the image, and thus corresponding to image regions of relevance.