Patent ID: 6023537
Filing Date: 2000-02-08
Classification: H04N

Abstract:
An image reading position error measuring device, comprising:an oblique line pattern, located outside of an effective image area, comprising a plurality of oblique lines with a fixed inclination to the main scan direction;reading means, extending in the main scan direction, for reading said oblique line pattern together with the original image positioned in said effective image area;setting means for setting an image size change rate for the original image;sub-scanning means which changes an original image scanning speed in the sub-scan direction according to the image size change rate;first calculating means for setting a window on image data of said oblique line pattern obtained through said reading means, and calculating a center of gravity of the image data in the window;controlling means for controlling movement of the window according to a value of the center of gravity obtained through said first calculating means; andsecond calculating means for obtaining an image reading position error for each of the main scan lines based on the value of the center of gravity and the image size change rate.