Picture blanking synchronisation video signal prepn. - uses max. values nearest to black and white levels in line for video amplifier control

摘要

The signal is intended for automated picture evaluation uses control signals for video amplifier derived from sections of the picture signal. A max. value nearest to the black level and to the white level is determined in each line of the video signal. The control range of the video amplifier is adjusted by the resultant mean value so that the mean voltage level of the control range of each line corresponds to the mean value of both max. values in the preceding line.