What does JPEG2000 mean?

 

When was JPEG2000 born?

 

Why a new standard?

 

Which are the aimed targets and characteristics?

 

Which are the new features introduced by JPEG2000?

 

Which is the JPEG2000 paradigm?

 

Which programs does JPEG2000 support?

 

How is the standard divided?

 

Is JPEG2000 already an international standard?

 

How can I compress images to the JPEG2000 format?

 

How are JPEG2000 files called?

 

 

 

 

 

 

 

 

 

 

What does JPEG2000 mean?

 

JPEG is the acronym of Joint Photographic Expert Group and is referred to a group of experts in the field of digital images. These experts work under the supervision of ISO/EIC and ITU/T, which care about standard accreditation.

JPEG2000 is a new project on which the group is working in order to add new features and capabilities to the current standard in digital image compression (JPEG baseline). This project started in 1996 and led to the first paper, known as JPEG2000 Part 1, in December 2000. In less than 6 months after the publication of JPEG2000 Part 1, several hardware and software products based on the new standard were announced and partially brought onto the market.

 

 

When was JPEG2000 born?

 

In 1996 the Joint Photographic Expert Group started working on a new image compression standard that would take the place of the well-known JPEG and would improve it. Some years later, JPEG2000 Part 1 paper was published and finally approved in December 2000. Then some extensions were issued (they are 6 – to be more precise); each of them was about specific applications of the standard.

 

 

Why a new standard?

 

The aim is to improve the trade-off between quality and bit rate and to offer more flexibility by the means of introduction of new concepts like ‘scalability’ and ROI.

 

 

Which are the aimed targets and characteristics?

 

The main target is to be able to compress images with a low bit rate, without losing in quality performances.

JPEG2000 wants to become the new standard for still picture representation and take the place of the previous JPEG standard.

 

 

Which are the new features introduced by JPEG2000?

 

This is a short list:

 

 

 

Which is the JPEG2000 paradigm?

 

Coding efficiency, multi-resolution, aimed bit rate, qualitative scalability, progression from lossless to lossy, tiling, improved error resilience, improved bit stream syntax, file format.

 

 

Which programs does JPEG2000 support?

 

Most of the new Image Processing software can process and decode files by the means of ad hoc plug-ins.

 

 

How is the standard divided?

 

From a formal point of view, JPEG2000 is divided into 11 different papers, which are called Parts in the standard terminology; six of them were added recently and one has been abandoned.

 

·         Part I: describes the minimum requirements that an encoder should have. Its aim is to create a set of basic options with the highest interoperability among different implementations.

·         Part II: contains optional extensions that enable an improvement in performances in several fields of application.

·         Part III: concerns with ‘Motion JPEG2000’, a standard for high quality Digital Video.

·         Part IV: is a set of validation tests in order to certify the correspondence of coding and decoding equipment to the standard.

·         Part V: set of software models that may be used as a reference in designing JPEG2000 products.

·         Part VI: its aim is to establish a set of specifications for the use of JPEG2000 in different applications such as fax, electronic publishing and numeric applications.

·         Part VII: abandoned.

·         Part VIII: JPSEC, it is about security.

·         Part IX: JPIP, interactive protocols and API (Application Protocol Interfaces).

·         Part X: JP3D volumetric images, it concerns with 3D images representation.

·         Part XI: JPWL, wireless applications.

 

 

Is JPEG2000 already an international standard?

 

Only few ‘Parts’ are already international standards. Moreover, the first part is an open system (completely free), differently from the second part that not only will it use different encoders from the first one and incompatible with it, but also it will be protected through the IPRs (Intellectual Property Rights). Documents from 3 to 6 will become standards within 2005.

 

 

Who has contributed to the draft of the standard?

 

The JPEG committee (www.jpeg.org)

 

 

How can I compress images to the JPEG2000 format?

 

At the moment it is possible to do it by using some applications that run under DOS (such as Kakadu); they allow to compress and decompress images and to open ‘.JP2’ files. It is also possible to benefit from the extended features of JPEG2000, such as ROI.

 

 

How are JPEG2000 files called?

 

JPEG2000 files can be identified by the ‘.JP2’ or ‘.JPX’ extensions; the former is the basic version and it has been studied for RGB or grayscale images; the latter has been studied in order to improve the potentiality of the format in case of photographic and non-photographic images and contains some fields that can be used for metadata (for instance when and where a picture was taken). Although the JPX format is used above of all for applications that require better performances, both formats are compatible and a JP2 reader can read a JPX file too. At the moment two other JPEG2000 formats are in development: JPM and Motion JPEG2000. The former can save compound images by using different kinds of compression; with the latter, one can acquire image sequences (for instance coming from video or photo-cameras).