Abstract: A digital registration circuit for a multi-tube television camera wherein correction quantities corresponding to positions on a target of an image pickup tube are stored in a digital memory. The digital signal for the correction quantity read out from the digital memory is converted into an analog signal which is supplied to a low-pass filter and smoothed. The smoothed signal is sampled at a sampling frequency higher than the frequency at which the correction quantities stored in the digital memory are read out and the sampled signal is converted into a digital signal. The digital signals sequentially produced are applied to a shift register, and four sequential sample values supplied from the shift register are added together in an adder. The shift register operates in such a manner that four samples are shifted one by one every adding time. An output signal from the adder is used for correcting registration, so that the generation of shading can be prevented.

Abstract: A television camera capable of correcting shadings caused by digital registration faculty employed in a multi-tube type color television camera. The television camera comprises differentiating circuits for generating differentiated waves of correction waveforms used for adjusting registration, and non-linear circuits for processing the differentiated waves. Outputs of the non-linear circuits control the gain of a video signal circuit so that components responsible for the generation of shadings can be removed from a video signal.

Abstract: A circuit for generating a signal for correcting deflection of electron beam, which circuit is advantageously used as, for example, a circuit for correcting registration in a multi-tube type color television camera. In the correction signal generating circuit, quantities of corrections at intersections defined by a plurality of lines extending in horizontal and vertical directions so as to divide a surface scanned by the electron beam into a plurality of areas are stored in terms of digital values. The digital signal read out from the memory is converted into an analog signal. The analog signal is then supplied to low-pass filter means. From the output signal of the low-pass filter means, quantities of correction are prepared for the scanning lines present between the two intersections located adjacent to each other in the vertical direction. In the circuit, the shading is positively prevented from occurring.

Abstract: A method and system for controlling the quantity of an electron beam in a camera tube in which scanning beam current scans a target electrode to be converted into signal current by the target electrode and this signal current is fed back in the form of a voltage signal to a beam control electrode through a feedback circuit, the amplification factor of this feedback circuit being selected to be smaller than the reciprocal of the maximum efficiency of conversion of the scanning beam current into the signal current.

Abstract: A method of and an apparatus for controlling the amount of the electron beam in a photoconduction type image pickup tube in which the signal corresponding to the return beam from the photoelectric conversion plane is detected, the detected signal is compared with a reference signal and amplified, and the resulting signal is applied to the scanning electron beam current control electrode. By appropriately determining a plurality of circuit constants the return beam can be maintained approximately at a constant value independently of the amount of light incident upon the photoelectric conversion plane.