Workshop on Electronic Texts · Library of Congress
SESSION IV-B
George THOMA In the use of electronic imaging for document preservation, there are several issues to consider, such as: ensuring adequate image quality, maintaining substantial conversion rates (through-put), providing unique identification for automated access and retrieval, and accommodating bound volumes and fragile material. To maintain high image quality, image processing functions are required to correct the deficiencies in the scanned image. Some commercially available systems include these functions, while some do not. The scanned raw image must be processed to correct contrast deficiencies-- both poor overall contrast resulting from light print and/or dark background, and variable contrast resulting from stains and bleed-through. Furthermore, the scan density must be adequate to allow legibility of print and sufficient fidelity in the pseudo-halftoned gray material. Borders or page-edge effects must be removed for both compactibility and aesthetics. Page skew must be corrected for aesthetic reasons and to enable accurate character recognition if desired. Compound images consisting of both two-toned text and gray-scale illustrations must be processed appropriately to retain the quality of each.
Text from Project Gutenberg, public domain in the United States.