Patent ID: 7688479

Claim:
A method, comprising: obtaining a calibrated image by detecting a calibration board approximately located at one side of a platform of a scanner, wherein the calibrated image is detected by a set of calibration photosensitive devices, and the calibration board comprises a pattern that varies along one or more of a plurality of axial directions of the scanner and wherein the plurality of axial directions comprise a y-axis indicating a direction of scanning and an x-axis oriented orthogonally to the y-axis, and wherein a z-axis is oriented orthogonally to both the x-axis and the y-axis; calculating a first optical path deviation in the z-axis based, at least in part, on a variation of the pattern to adjust a scanned image according to a displacement of the calibrated image detected by the set of calibration photosensitive devices; and calculating a second optical path deviation twisting around the y-axis based, at least in part, on the first optical path deviation in the z-axis to adjust the scanned image.