A prototype system for the electronic storage and retrieval of document images

Abstract

A prototype system has been implemented for electronic scanning, digitization, storage, retrieval, and display of images of biomedical documents. Paper documents are scanned and digitized at a scan density of 200 picture elements (pels) per inch by either a high-speed loose-leaf scanner with an automatic document transport or a book scanner with a manual book holder. Each scanner employs a high-resolution charge-coupled device (CCD) linear array operating at a sampling rate close to 10 MHz. The analog output signal of the CCD array is digitized into 1 bit per pixel two-tone images by means of dynamic thresholding. The digitized images are stored on magnetic disks to be processed and will eventually be transferred onto optical disks for archival storage. Existing on-line bibliographic databases developed by the National Library of Medicine are used as directories for the retrieval of document images. These images are displayed at a resolution of 200 pels/inch in both soft-copy (raster-refreshed CRT) and hard-copy forms. This prototype system, developed as part of a research and development program, offers the opportunity to investigate the areas of document image enhancement, image compression, and omnifont text recognition and to conduct experiments designed to answer key questions on the role of electronic document storage and retrieval technology in library information processing and the preservation of library documents.