Pixels in an array of image sensor pixels contain photo-sensors. In response
to illumination of a photo-sensor, an initial signal is generated. Multiple comparison
signals are also generated based on the initial signal. One of the comparison signals
remains internal to the pixel, and other comparison signals are transmitted to
neighboring pixels. Within a pixel, the internal comparison signal is compared
to a sum of comparison signals received from neighboring pixels. Based on the comparison,
a data value may be latched and used for indicating a relative difference in pixel illumination.
