초록

At low light levels, the floating diffusion output stage of a CCD imager has the peaks of the reset pulses applied to its reset gate reduced. This introduces spatial integration in the direction of line scan that improves the signal-to-noise ratio of the video samples supplied as imager output.

대표청구항 ▼

In the method of operating a CCD imager of the type having a floating diffusion output stage, said method comprising the steps of: periodically introducing charge packets descriptive of image elements under the floating diffusion; sensing the potential of the floating diffusion following the introdu

In the method of operating a CCD imager of the type having a floating diffusion output stage, said method comprising the steps of: periodically introducing charge packets descriptive of image elements under the floating diffusion; sensing the potential of the floating diffusion following the introduction of each charge packet; and providing, during reset intervals following each sensing of potential and preceding the next introduction of a charge packet, a conductance path for transfer of charge stored under the floating diffusion to a reset drain-the improvement for providing a video signal with improved signal-to-noise ratio responsive to low light input levels to the imager, which improvement in said method comprises the step of: reducing the conductance of the path provided during each reset interval for transfer of charge stored under the floating diffusion to the reset drain to such value as to slow the transfer of the charge stored under the floating diffusion to the reset drain during each reset interval in inverse relation to the level of the charge stored under the floating diffusion, whereby there is integration of the charge packets formed in response to low light levels to increase the level of the signal component of sensed potential respective to the noise component thereof.