An image scanner has a calibration strip, preferably the full width of the scanline, that is visible to a photosensor array continuously during a scan. For example, the calibration strip may be on a moving carriage. At least one separate array of photosensors is used to continuously monitor the intensity,...http://www.google.es/patents/US20020100863?utm_source=gb-gplus-sharePatente US20020100863 - Optical image scanner with color and intensity compensation during lamp warmup
Optical image scanner with color and intensity compensation during lamp warmup