Optical image scanner with moveable calibration target

摘要

A scanner has a calibration target that can be moved in front of the scanline during a scan. This enables multiple calibrations during a scan. A full-color calibration can be performed during scanning without the need for a separate array of photosensors. Scanning can start as soon as the lamp provides sufficient light for scanning, without waiting for the lamp to stabilize. It is not necessary to keep the lamp on, or to keep the lamp warm.