Method and apparatus to correct distortion of document copies

摘要

Pages of books are copied without distortion due to curvature of the page near the book binding or the distortion in a copied page is corrected using the spacing of equidistant bars on tape strips applied to the top and bottom edges of a page before copying. The tape is preferably transparent and rather narrow and easily attached to a page to be copied. The first step in the distortion correction procedure is to locate the bars at the top and bottom of the page. The distortion of the spacing between the imaged bars is computed based on the known distance between the equidistant bars. The computed distortion of the spacing is then input to a distortion correction algorithm. The output of the distortion correction algorithm generates a corrected image. This image may also optionally delete the bars so that they are not printed in the copy. The corrected image is then copied.