Comparison of Advanced Compression for Bitonal Images
This study extends the example tables for JBIG2-compressed PDF at both the Adobe and CVision websites, and then also adds a study of typical technical papers. Use this study to see for yourself the relative merits of advanced compression technologies for both DjVu and PDF, as applied to bitonal scanned images.
Use the displayed sizes to compare the compression effectiveness. Click the size hyperlinks to open files to compare actual performance.
Adobe Study - Extended
A comparison by James Rile, PlanetDjVu, Sept. 19, 2002, updated Oct. 22, 2002
...a DjVu and CVision JBIG2-PDF extension of...
All Adobe and CVision PDF files have been copied to the PlanetDjVu server, so you can make a good comparison of the relative performance and speed of PDF and DjVu files.
Remember, it is not just file size that is a factor in web performance, it is also file format design and the file viewer plug-in design. I notice a short lag time in the decoding of JBIG2-compressed PDF pages from Capture, while there is barely any lag time at all PDF pages from CVIision and in DjVu. Check for yourself!
DjVu files were produced (and OCRed) at the Any2DjVu conversion server.
CVision JBIG2-PDF files were produced by CVIsion using the latest Build 19 of their compressor.
CVision has introduced some clever text compression in addition to JBIG2 compression, which is why their OCRed JBIG2-PDF is actually smaller than DjVu!
CVision Study - Extended
A comparison by James Rile, PlanetDjVu, May 14, 2002, updated Oct. 4, 2002
...a DjVu and Acrobat Capture JBIG2-PDF extension of...
NOTE: You need Adobe Acrobat Reader 5.0 or later to view JBIG2-encoded PDF files.
Technical Paper Comparison from JRA
This is a set of 59 technical papers presented at a symposium. The scanned text is clean and only one or two fonts are used. This study demonstrates compression levels that can be achieved with the scanning and conversion of clean, laser-printed scientific and technical papers.
To view CIF files, you need the CVista Viewer Plug-in, available from: http://www.cvisiontech.com/cvista_viewer.html
To view DjVu files, you need the DjVu Web Browser Plugin, available from:
To view JBIG2-PDF files, you need Acrobat Reader 5.0 or above.
To compare the different formats, you want to test performance and factor these results with the compression levels achieved. Performance is best measured using files that have not yet been opened, and are therefore not in the browser's cache - they are directly opened from the URL address. You have plenty of unopened file links to test with below.
We observe that JBIG2-PDF files from CVision display faster than JBIG2-PDF from Acrobat Capture, due to faster decoding in the Acrobat Reader Plugin. DjVu files display twice as fast as any PDF alternative, due to having a file and plugin that is designed specifically for web delivery.