초록 ▼

An image sensor causes a solid-state imaging device, at the scanning of an image, to release in succession a dark current signal generated in the solid-state imaging device and a scanning signal containing said dark current signal, subtracts said dark current signal from said scanning signal by a di

An image sensor causes a solid-state imaging device, at the scanning of an image, to release in succession a dark current signal generated in the solid-state imaging device and a scanning signal containing said dark current signal, subtracts said dark current signal from said scanning signal by a differential circuit to obtain an image signal corresponding to said image, and so regulates by means of an integrating time control circuit and in response to the level of said image signal, the image signal integrating time of said solid-state imaging device as that said image signal remains within a certain level range. In an improvement of the present invention there is further provided means for forcedly resetting the image signal integrating time to be determined by said integrating time control circuit to a shorter time in case the image signal reaches an inappropriate level while said image signal integrating time is fixed at a determined level without renewed control thereof.

대표청구항 ▼

A radiation sensing system comprising: (A) radiation sensing means of the signal integrating type arranged to produce a dark current signal and a radiation sensing signal containing the dark current signal; (B) means for conducting dark current compensation on said radiation sensing signal on the ba

A radiation sensing system comprising: (A) radiation sensing means of the signal integrating type arranged to produce a dark current signal and a radiation sensing signal containing the dark current signal; (B) means for conducting dark current compensation on said radiation sensing signal on the basis of said dark current signal and for producing a dark current compensated sensing signal; (C) means for controlling a signal integrating time of said sensing means on the basis of said dark current compensated sensing signal; (D) means for detecting the condition that the dark current compensated sensing signal is below a predetermined level while the signal integrating time remains unchanged; and (E) means for resetting the signal integrating time of said sensing means from a previously set time to a shorter time, said resetting means including a timer circuit and being arranged to reset the signal integrating time, responsive to detection of said condition by said detecting means for a period determined by said timer circuit while the signal integrating time remains unchanges.