METHOD FOR ADJUSTING RESOLUTION OF A SCANNING

The present invention provides a resolution adjustment method for adjusting the resolution of a scanning module. The scanning module is installed in a scanner for scanning a document and comprises a case with a line-shaped opening on its top for receiving light from the document, a sensor installed in the case and comprising linearly arranged sensing units for scanning the light from the document and generating correspondent image signals, a lens installed in the case for converging the light from the document to the sensor, and a mirror module installed in the case for passing the light from the document through the lens to the sensor. The resolution adjustment method provides the scanning module with a calibration picture for generating a calibration image which comprises two groups of parallel lines in two directions for calibrating the resolutions of the sensor in the two different directions. Then, the magnitude of the image is measured corresponding to the two groups of parallel lines and the position of the scanning module is adjusted until the resolutions represented by the image signals corresponding to the two groups of parallel lines are roughly equal.