Abstract: The present invention relates to a method for compressing an image data in real time. At first, the present invention divides an image, which is got after a pre-scanning process, into plural lines. Each line is divide into several blocks, whose sizes are the same. Each block comprises plural pixel values. A pixel value of a block is saved in the buffer completely to become the first datum. The pixel value is usually the minimum pixel value. Then plural differences, which are between the first datum and the plural pixel values of the block, are calculated. One of the plural differences, which are not equal to zero, is saved in the buffer completely to become the second datum. The difference, which is not equal to zero, is usually a minimum difference. Using the second datum to be a divisor and using the plural differences to be dividends will get plural specific values of plural differences to the second datum.

Abstract: An optical scanner equipped with plug-in calibration film, which the optical scanner provides light incident upon a transmission-typed document and catches the image signals of the transmission-typed document by an optical chassis. The optical scanner equipped with plug-in calibration film includes a scanning zone and at least one attachment. The scanning zone is capable of providing for placing the transmission-typed document. The attachment is capable of providing a calibration film for enabling the optical chassis to retrieve the image signals so as to improve the image brightness.

Abstract: A method for capturing images useful in a scanning system is provided. The present method comprises performing a preview scan of a picture and then displaying the preview image of the picture on a screen. Selecting a scanning area of the preview image and simultaneously performing a first normal scan of the picture from an initial scanning position relative to the picture. When the scanned area of the first normal scan corresponds to the selected scanning area, the scan image produced by the first normal scan is displayed. Otherwise, a second normal scan of a portion of the picture that corresponds to the selected scanning area is performed to produce a final scan image.