Pandora

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Pandora

• a box full of data within a JPEG 2000 image file

Greg Colyer, Elysium Ltd Crowborough, UK Rui
Costa, ADETTI Lisbon, Portugal EVA 2001
Scotland, Glasgow, 27 July 2001
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Outline

• Context
• Image coding principles
• JPEG 2000 and Pandora
• architecture
• examples
• Future RD directions and applications
• Links

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Pandora

• A novel web-based application ofJPEG 2000
• integrating markup metadata withadvanced imaging
  technology
• a prototype for the Portable Networked Document
• One of the outputs from MIGRATOR 2000

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JPEG 2000

• A new system for coding still images
• ISO/IEC 15444-12000
• Codestream syntax based on JPEG
• Wavelet-based compression algorithm
• Other features, e.g.
• file format
• Regions of Interest (ROI)

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MIGRATOR 2000

• A European FP5 IST project
• NETIMAGE, Thales, UCL (Louvain-la-Neuve), SACD,
  ADETTI, Elysium, Alinari
• About the migration of imaging tools to JPEG 2000
• http//www.migrator2000.org/

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Image compression

• Images are highly structured
• Eyes/brains see only certain kinds of structure
• So it is possible to compress image data
• by spotting the pattern and encoding it more
  compactly
• by eliminating visually unimportant information

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Typical algorithm

• Transform the data into a more appropriate form
• Reduce the precision of some of the data
• quantising
• Represent the quantised data efficiently
• encoding

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Image file formats

• Are about encapsulation of image data within a
  helpful structure
• including metadata
• The de facto file format for JPEG is JFIF
• There is an official file format, SPIFF
• more advanced but little used
• JPEG 2000 Part 1 defines JP2
• basic but extensible (JPX, JPM, )

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JP family architecture

• A file is a sequence of boxes
• A box consists of
• 4-byte length
• 4-byte type identifier
• content
• The content is a sequence of fields and/or boxes,
  as defined for each type of box
• so hierarchical

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Example boxes

• JPEG 2000 Signature box (always first)
• Contiguous Codestream box
• Codestream Header box
• Label box
• XML box

jP
jpch
xml
jp2c
lbl
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Whats in a name?

• Boxes can be labelled, including
• codestreams (image data)
• XML documents (metadata)
• Entities within the file can then be referred to
  from outside it

jpch
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Components of Pandora

• Addressing strategy for labelled objects
• http//www.my.photos/beach.jpx/sunset
• Use of web page markup as metadata
• http//www.my.photos/beach.jpx/story
• Transcoding options on the server
• JPEG 2000 to JPEG, or XML to HTML
• different image qualities
• different image sizes

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Transcoding

• Current web browsers do not support JPEG 2000
  natively (or XML)
• Transcoding to JPEG (or HTML) provides a smooth
  upgrade path
• next step plug-in or Java applet
• Advanced delivery options take advantage of new
  JPEG 2000 features
• scalability by quality/resolution

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JPEG 2000 coding

• Wavelet transform is related to subsampling
• Transformed data are coded in order of
  significance
• Coded data are located in packets
• can be reordered without decoding
• can be discarded safely

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All kinds of metadata

• XML need not be page markup
• JPEG 2000 Part 2 defines many specific metadata
  boxes, based on DIG35
• Not all metadata is in XML boxes
• specific IPR box
• Pandora is just one (novel) example of the power
  of metadata

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Pandora summary

• Applies JPEG 2000 technology on the web
• Provides an upgrade path
• transcoding for existing browsers
• Self-contained and portable, but with the online
  character of HTML
• User-aware intelligent content delivery

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Future RD directions

• A JPEG 2000 Transfer Protocol
• networked packets
• connectionless?
• user-driven dynamism?
• DIG35 metadata processing
• PND specification
• Encryption/security
• ROI

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Application examples

• Image bank
• free versus fee
• Colour separation for printing
• Museum guide/website
• handheld device has small screen, low bandwidth
• Consultants PDA/hospital server/GPs PC
• lossless encoding important in medical arena

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Want to join us?

• Successor project to MIGRATOR 2000
• 7th IST call deadline 17 October
• Future parts of JPEG 2000 may include
• Security
• Interactivity and Protocols
• Commercial research work ortechnology
  partnership
• Joint product development

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Links

• Pandora Home Page
• http//www.migrator2000.org/pandora
• http//public.migrator2000.org/pandorademo
• E-mail
• greg_at_elysium.ltd.uk
• rui.costa_at_webmais.pt (new)

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Pandoras box /pandOr_at_z "bQks/ n. phr. New
Shorter OED

• M16. f. Gk Pandora, lit. all-gifted, name in
  Greek mythol. of the first mortal woman, on whom,
  when made by Vulcan, all the gods and goddesses
  bestowed gifts, f. as pan- doron gift.
• In Greek mythology, the gift of Jupiter to
  Pandora, a box enclosing all human ills, which
  flew out when the box was foolishly opened (or in
  a later version, containing all the blessings of
  the gods, which with the exception of hope
  escaped and were lost when the box was opened)
  gen. a thing which once activated will give rise
  to many unmanageable problems.