摘要 |
A device for quickly and precisely determining a scan start point and improving scanning quality for an image scanner is disclosed. The image scanner includes a photo-processing device and a scanning platform for placing thereon a document to be scanned. The scanning platform is printed with a background region and two color blocks. The two color blocks are separately enclosed by the background region and are of different color from the color of the background region. The first color block has a first specified point therein being a predetermined shift to the scan start point along a specific direction. The second block has a second specified point corresponding to the first specified point in position. The photo-processing device moves a predetermined distance L0 from the home position to a pre-scan position overlapping with the two color blocks by four reference points, read the coordinates of the four reference points, then moves a calculated distance L1 from the pre-scan position to the first specified point, and moves another predetermined distance L2 from the specified point to the scan start point along the specific direction to start scanning. The distance L1 can be automatically adjusted to cover the installation error of the photo-processing device. According to the coordinates of the four reference points, the coordinates of the two specified points can be calculated, thereby realizing a deflection rate and/or an amplification error of a scanning result. For another image scanner disclosed herein, the movement of the distance L0 can be omitted by having the color blocks located at the home position which serves as the pre-scan position.
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