In the disclosed element, a number of line shaped sensors each includes a plurality of P-N junctions each of which accumulates a charge corresponding to the amount of light incident thereon. A number of registers, one for each sensor, each defines addresses coupled to respective P-N junctions of the corresponding sensor to have the charge accumulated on each P-N junction transferred to the respective address in each register so that time sequential signals can be obtained from each register. A collection register has an address coupled to each of the other registers to store the time sequential output signals so that the stored signals can be read out sequentially. A gate arrangement connecting the output of the first registers to each address controls the time interval during which the time sequential signals of the first registers are transferred to the accumulating register.