Evaluating JPEG2000 for Evaluating JPEG2000 for Cultural Heritage Cultural Heritage OrganizationsOrganizations

Gretchen GueguenDigital Archivist

9/13/2011

Evaluating JPEG2000 for Cultural Heritage Organizations by Gretchen Gueguen is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

What We’ll Cover…

• What is JPEG2000• What are the advantages?• What are the risks?• How do I decide if JPEG2000 is the

standard for me?

JPEG2000

Dry, dictionary definition:

JPEG 2000 is an image compression standard and coding system. It was created by the Joint Photographic Experts Group committee in 2000 with the intention of superseding their original discrete cosine transform-based JPEG standard (created in 1992) with a newly designed, wavelet-based method.

JPEG2000

• Format for still and moving images• Smaller than some other high resolution

formats • Ability to compress through lossless or

visually lossless algorithms• Scalable display• More robust embedded metadata• Error resilience• Supports images at least up to a terabyte

Risks

• Uptake in adoption, but not as fully compatible as TIFF or JPEG– Digitization– Display/handling

• Unfamiliarity to administrators and users

• Complexity can lead to long-term riskshttp://www.dlib.org/dlib/may11/vanderknijff/05vanderknijff.html

Decision-making

Evaluation Factors:•Compression and savings possible•Scalability vs. Derivatives•Tools Available•Conversion projects•Adoption by peers

JPEG2000 compression

• True Lossless (reversible)– Can still achieve significant size

reduction

• “Visually” Lossless (irreversible)– Lossy compression with no visible effect

• Lossy (irreversible)– Lossy compression with visible effects

Compressions and savings

TIFF = 35 Mb 1:1/2:1 = 4.96 Mb (86% reduction)

4:1 = 4.56 Mb (87% reduction) 6:1 = 3.89 Mb (89% reduction) 10:1 = 2.87 Mb (92% reduction) 25:1 = 1.39 Mb (96% reduction) 50:1 = 0.72 Mb (98% reduction) 100:1 = 0.37 Mb (99% reduction)

Source: http://jpeg2000wellcomelibrary.blogspot.com/2010/08/as-result-of-our-decision-to-go-lossy.html

Compression rate

• Testing compression algorithms to get best trade-off– Even lossless can save a lot– At what point are your returns for

further compression too small

Evaluating compression

Comparing Differences using Photoshop•http://jpeg2000wellcomelibrary.blogspot.com/2010/10/guest-post-examining-losses-simple.html

•http://www.digitizationguidelines.gov/still-image/documents/Comstock.pdf

Lossy Compression and Predictability

JPEG2000 Scalability

Scalability vs. Derivatives

• JPEG2000 can natively scale to different sizes

• Do you WANT to only have one copy?– Preservation master– Production master– Access copies

(full, high, and/or medium resolutions)

– Thumbnails

JPEG2000 Tools: Image Creation

JPEG2000 Tools: Display

JPEG2000 Tools

• Serve and Render–Kakadu + Djatoka (open source*)

http://www.kakadusoftware.comhttp://sourceforge.net/apps/mediawiki/djatoka/

–LuraWave (commercial)https://www.luratech.com/products/imaging-solutions/lurawave-jp2-image-content-server.html

JPEG2000 Tools

• Online enhancement– Internet Archive BookReader (open

source)http://openlibrary.org/dev/docs/bookreader

–Library of Congress Newspaper Viewer (open-source)http://sourceforge.net/projects/loc-ndnp/

JPEG2000 Tools

• Create or edit–Photoshop (commercial)• j2k plugin for more advanced workhttp://www.fnordware.com/j2k/

–Newer versions of Silverfast (commercial)–GIMP (open source)• lower level support

Backlog Conversions

• TIFF to JPEG2K backlog?– Infrastructure – Time• Testing• Migration• QA

Adoption by Peers

• Library of Congress• Internet Archive• Wellcome Library• Google• LexisNexis• Multiple Universities…

ECU Example

• JP2 master going forward. No backlog conversion (at this time)

• Scan as tiff due to software constraints, convert to JP2 during post-production clean-up phase

• Save the master in offline storage• Deliver a derivative JP2 for access for

maps and books in a zooming book viewer• Use a GIF thumb because of load issues

UVa Example

• Uncompressed tiff as preservation master• 186,000+ jp2 for access purposes only– Maps, books, and sheet music– Other things just in tiff at the moment, not

available yet• Two different lossy compression algorithms for

access based on average compression toleration– One for large-scale maps– One for everything else

• Dynamically-generated thumbnails

Learn More…

JP2K-UK Working Group Wiki•http://wiki.opf-labs.org/display/JP2/Home

JP2k at Wellcome Library Blog•http://jpeg2000wellcomelibrary.blogspot.com/

JPEG 2000 for the Practitioner•http://www.dpconline.org/events/details/19-jpeg-2000-for-the-practioner?xref=19

Library of Congress JPEG2000 Workshop presentations•http://www.digitizationguidelines.gov/resources/jpeg2000.html

UConn survey on JPEG2000 adoption rate•http://digitalcommons.uconn.edu/libr_pubs/19/

DPBestFlow.org•http://www.dpbestflow.org/