Patent ID: 6381043
Filing Date: 2002-04-30
Classification: H04N

Abstract:
An image scanner, comprising:a photo-signal processing device moving along a specific direction from a home position for picking up an image of a scanned document, and converting said image into digital data to be further processed; and a scanning platform for placing thereon said document, having thereon: a first color block located in front of said scan start point along said specific direction, and being of a first color; a second color block located in front of said scan start point along said specific direction, separated from said first color block, and being of a second color; and a background region enclosing said first and said second color blocks, having a first and a second interfaces with said first and said second color blocks, respectively, and being of a third color different from both of said first and said second colors; wherein coordinates of a first reference point and a second reference point located in said first interface, and coordinates of a third reference point and a fourth reference point located in said second interface are read when said photo-signal processing device moves to a pre-scan position and performs a pre-scan operation; said coordinates of said first and said second reference points correlate with a shift from said pre-scan position to a first specified point of said first color block along said specific direction through a first correlating mathematical function; said coordinates of said first and said second reference points correlate with a coordinate of said first specified point through a second correlating mathematical function; said coordinates of said third and said fourth reference points correlate with a coordinate of a second specified point of said second color block, which corresponds to said first specified point in position, through a third correlating mathematical function; a scan start point of said photo-signal processing device for picking up said image of said scanned document is determined according to said shift from said pre-scan position to said first specified point, and a predetermined shift from said first specified point to said scan start point along said specific direction; a deflection rate is determined according to said coordinates of said first and said second specified points; and an amplification error is determined according to said coordinates of said first and said second specified points, and a predetermined distance between said first and said second specified points.