#0307 - What are JPEG 2000 formats - file extensions .jp2, .jpx
JPEG 2000 is the latest series of standards from the JPEG committee.
The original standard for digital images, JPEG was developed
15 years ago, and with the major increase in computer technology
since them, it was felt to be time for a new standard capable
of handling many more aspects than simply making the digital
image files as small as possible. JPEG 2000 uses 'wavelet'
technology, and as well as being better at compressing images
(up to 20 per cent plus), it can allow an image to be retained
without any distortion or loss. Simply sending the first part
of such a 'lossless' file to a receiver can result in a lossy
version appearing (like present JPEG) - but continuing to transmit
the file results in the fidelity getting better and better
until the original image is restored.
One early use of JPEG 2000 will be as a base file format in image
archives and databases. Traditionally, image archives store multiple
copies of an individual files at varying resolutions and quality
levels so that they can supply appropriate image data on request.
In addition, considerable metadata is held about each image to
allow it to be easily classified and retrieved.
JPEG 2000 files typically can have extensive metadata stored with
them, in a standard compliant XML environment. As well as allowing
selected metadata from an image database to be distributed to its
users, this does permit interchange of image files with metadata
between databases, and removes the need for an extensive manual
data entry stage when cataloguing new images. In addition, the
files can be stored at high quality in a lossless, color managed
environment, with conversion to lower resolution or lower quality
performed 'on the fly'. The ability of part of a JPEG 2000 file
to be used for generation of such modified images also means that
it becomes practical to provide other capabilities on demand.
One example might be to watermark each image as delivered, not
only with details which communicate authorship or ownership, but
also transactional information. This could include licensing restrictions,
details of the customer, or information which would allow the image
to be easily recognized through some automated process designed
to test for breaches of copyright.
JPX - a new file format, JPX, based on JP2 but supporting multiple
compositing layers, animation, extended colour spaces and more
Last Reviewed: 6. March
2006
2006 Contex A/S. All rights reserved.
