CMOS imager design for fast centroid readout

Numerous applications of imaging systems involve the determination of the centroid location of a localized region of high intensity (a "spot") that is easily distinguished from the background. The goal of this work was to tailor the design of a custom CMOS imager to facilitate the centroid-location task. On-pixel circuitry, readout methods, on-chip post-readout processing and other factors were considered in the design process. The \´design process\´ included system modeling, simulation and experimental validation as well as chip-level design. A triangulation rangefinder instrument was constructed to evaluate imager alternatives. The precision of the range determination is proportional to the precision of the location of the centroid of the image of an optical spot. Range measurements are presented to demonstrate that uncertainty in centroid position, the dominant error source, can be significantly reduced by averaging. A novel CMOS imager design concept is described. Using on-chip processing and a \´pixel-binary\´, row/column-parallel readout scheme, range values are expected to have an update rate as high as 1 MHz. Key aspects of the chip design are evaluated, especially as they pertain to update rate and the use of on-chip averaging to enhance precision.