SYSTEM AND METHOD FOR DOCUMENT SIZE DETECTION IN A DOCUMENT REPRODUCTION DEVICE

摘要

What is disclosed is a system for determining the size of a document on a platen of a document scanning device. In one embodiment, the scanning device comprises in part: a transparent pane (platen) whereon a hardcopy print is placed; a scan head comprising optical sensors which output a signal comprising an image of that hardcopy print; a plurality of LEDs positioned such that a topside of the platen is illuminated; and a processor for instructing the scan head to pre-scan the print. During the pre-scan, optical sensors comprising the scan head sense light from the LEDs of areas of the platen not covered by the hardcopy print at a first intensity and sense light from the LEDs of areas of the platen which are covered by the print at a second intensity. The processor determines the size of the hardcopy print from the first and second intensity levels.

主权项

1. A method for determining a border of a hardcopy print placed on a platen of a document scanning device, the method comprising:
placing a hardcopy print on a platen of a scanning device comprising, at least in part, a scan head with a first set of light emitting diodes (LEDs) as a normal scan light source for illuminating a front-side of said hardcopy print during a normal scan and optical sensors which sense an intensity of light at each sensor's respective X/Y location as said scan head moves beneath said platen; placing an acrylic sheet with a second set of LEDs as a pre-scan light source for illuminating a back-side of said hardcopy print during a pre-scan; and performing said pre-scan of said hardcopy print placed on said platen comprising:
activating said light source such that said back-side of said hardcopy print is illuminated on said platen;using said scan head to scan said hardcopy print, said optical sensors sensing light from said pre-scan light source of areas of said platen not covered by said hardcopy print at a first intensity, said optical sensors sensing light from said pre-scan light source of areas of said platen covered by said hardcopy print at a second intensity; anddetermining, from said first and second intensities, a border of said hardcopy print.