US Patent 9319611 Image sensor with flexible pixel summing

An image sensor can include pixels that are grouped into subsets of pixels, with each subset including three or more pixels. A method for asymmetrical high dynamic range imaging can include capturing an image of a subject scene using a single integration time for all of the pixels. In a subset of pixels, charge in N pixels is read out and summed together. N represents a number that is between two and one less than a total number of pixels in the subset. Un-summed charge is read out from one pixel in the subset. The un-summed charge and the summed charge are combined when producing a high dynamic range image.