Photosensitive apparatus in which an initial charge on a photodiode is sampled and then retransferred to the photodiode

摘要

In a photosensitive device wherein a photodiode is operated by placing an initial fat zero charge thereon before the integration of a light-induced signal, the actual dark level signal created by the fat zero charge is sampled with each readout from the photodiode, and then retransferred to the photodiode. After integration, the sampled dark level is subtracted from the total signal level on the photodiode. In this way both fixed-pattern and thermally-induced noise is obviated.