Dark current measurement and correction for video from field-transfer

Abstract

In a television camera including an imager of the field-transfer type having A, B and C registers, an indication signal representative of dark current response accompanying the video signal is generated by comparing first and second signals representative of charge packets derived from the B and C registers, respectively. Specifically, the first signal is generated when the C register supplies signals supplied from the B register which includes substantially no photo-responsive components transferred from the A register. The second signal is generated when the C register supplies signals after the signal supplied from the B register have already been read out and while no new signals from the B register are being transferred into the C register and therefore represents absolute black.