A significant amount of
information in the world is still on paper. Many of those paper documents
include color graphics and photographs that represent significant invested value.
Almost none of that rich content is on the Internet, however, because scanning
such documents and publishing them on the Web has been problematic at best. At
the high resolutions necessary to preserve image quality and text readability,
file sizes become too large for acceptable download speed. Reducing the
resolution to achieve satisfactory download speed results in decreased quality
and legibility. Conventional JPEG and GIF encoding techniques have only begun
to solve this problem. As a result, Web content developers frequently cannot
utilize the information contained in existing printed materials.
DjVu® technology addresses this problem by segmenting
scanned documents into layers. Each layer is then encoded according to the
method that yields the best results for image size and clarity. The resulting
DjVu files are very small and preserve the clarity of the original documents
even at file size reduction ratios of 1000:1 and above.
This section covers the following topics: