An imaging system includes a plurality of pixels. A pixel readout circuit produces a plurality of first image frames from those pixels. An image output circuit produces a plurality of second image frames and operates to produce a second image frame from more than one of the first image frames. The pixel readout circuit is enabled to produce the first images frames at a rate faster than the image output circuit produces the second image frames. Through combining first image frames, by averaging or other statistical combinations, the photon shot noise of second image frames is reduced. Photon shot noise affects images with high light levels more than those with low light levels and, as such, the system processing alters the rate of first image frames dependent on the current light levels.
Image sensor noise reduction