Abstract: Systems and methods for processing a sheet having a printed underside. A gap between a feeder and a processing machine provides visibility to the printed underside, cameras capture images of the printed graphics through the gap, and a processor stitches the captured images together into a continuous image of the printed underside, including registration marks, corners or edges, and a sheet identifier. Processing instructions are retrieved from storage using the detected sheet identifier and are executed along processing paths calculated from detected information regarding locations of the registration marks and the corners or edges. A material guide positioned above the material path may be configured to constrain the sheet vertically as it passes over the gap and to reduce overhead light from interfering with the image capture.