Analysis of image features - using electron-beam scanning of lines of image and comparison of video signal with reference

摘要

An information signal is suppressed at the start of a line scan for a period at least equal to the maximum extent of an image feature in the line direction. The same applies to an information signal suppressed in the frame direction. In the path of the information signal there is a gate (28) and a control pulse generator (30) connected to the synchronising stage (18) is switched to the control input of the gate. At the beginning of a scan in the line and frame directions the gate is adjustably closed by control pulses generated by the generator. There is a video signal source and a reference signal source.