FLATBED SCANNER AND METHOD FOR CONTROLLING SAME

A flatbed scanner includes a transparent window and an optical ruler close to the transparent window along a scanning direction. The optical ruler has at least one oblique line arranged thereon. The flatbed scanner includes a scanner head having a scanning width larger than the width of the transparent window for capturing an image of the optical ruler while the scanner head is being progressively moved by a step motor. The flatbed scanner further includes a processing unit for calculating a jag width of a captured oblique line in the captured image and a controlling unit for controlling the step motor to adjust the speed of movement of the scanner head according to the jag width of the captured oblique line.