The control method is associated with a frame information transfer in accordance with the so-called accordion principle in which information shifts are locally effected with an opening, a transporting and a closing phase. The opening phase involves an enlargement of sensor element areas in a column direction in which a shift is effected during the transporting phase. The closing phase involves a reduction in the column direction of the enlarged areas (IE, BE, SE) at the appointed locations. In the presence of a sensor black level section (BLS) shielded from radiation and arranged between an image section (IS) and a storage section (SS) of the frame transfer sensor (FTS), clock pulse signals are applied to the black level section (BLS) after a frame information transfer period and during a black level generation period, which clock pulses lead to a transporting phase and a closing phase in accordance with the accordion principle, a black level reference is obtained which leads to a correct black level information in a picture signal to be supplied by a sensor output (OT).