1. A method comprising: producing two or more measurements by an image sensor having a pixel array, each of the two or more measurements comprising information contained in a set of sign-bits, the producing of each measurement of the two or more measurements comprising (i) forming an image signal on the pixel array; and (ii) comparing accumulated pixel currents output from at least some pixels of the pixel array in accordance with the image signal and at least a portion of a set of pixel sampling patterns to produce the set of sign-bits of the measurement; buffering at least one measurement of the two or more measurements to form a buffered measurement; comparing information of the buffered measurement to information of the two or more measurements to produce a differential measurement; and combining the differential measurement with information of the set of pixel sampling patterns to produce at least a portion of one or more digital images relating to one or more of the image signals formed on the pixel array.