CIRCUITRY FOR DISPLAYING ISODENSITY LINES IN AN IMAGE

摘要

A device for displaying isodensity lines of a radiation image on a CRT includes a radiation detector that provides a video signal that varies with the scanned radiation. A selector responsive to the video signal supplies first and second output signals. The first output signal is limited to a range between a given minimum and a given maximum value of the input signal and the second output signal is limited to a minimum value equal to the given maximum value of the input signal. The two output signals are subtractively combined and the resultant signal is applied to the control electrode of the CRT to vary the beam intensity.