Pixels in an array of image sensor pixels contain photo-sensors and circuits
having inputs connected to the photosensors. The circuits have feedback loops for
reducing fixed pattern noise in the array. Output from each pixel is used to latch
a multibit counter value supplied by a global counter. Each feedback loop preferably
includes a pair of alternately-toggling switching transistors to minimize unwanted
charge injection. An image sensor according to the invention can be used for, e.g.,
motion sensing.
