This transform has similar complexity as the separable wavelet transform while providing better energy compaction and staying critically sampled, which makes it a good candidate for compression applications. The increased decorrelation offers relatively good performance compared to state-of-the-art coder, even without complex adaptive high order models. To illustrate this, two simple separable wavelet and oriented wavelet codecs have been designed, using a non-adaptive first-order generalized Gaussian model for each subband. While the performance of this coder could be improved by using rate-distorsion optimization or better quantization techniques like TCQ, it performs within 1 dB from the state-of-the-art coders. Besides, the model is simple enough to apply efficient error resilient entropy coding, which is ...

[http://www.irisa.fr/temics/Equipe/Chappelier/owavelets/]

 In computing, JPEG (pronounced JAY-peg; IPA: /ˈdʒeɪpɛg/) is a commonly used method of compression for photographic images. The name JPEG stands for Joint Photographic Experts Group, the name of the committee that created the standard. The group was organized in 1986, issuing a standard in 1992, which was approved in 1994 as ISO 10918-1. JPEG is distinct from MPEG (Moving Picture Experts Group), which produces compression schemes for video.

The JPEG standard specifies both the codec, which defines how an image is compressed into a stream of bytes and decompressed back into an image, and the file format used to contain that stream.

The compression method is usually lossy compression, meaning that some visual quality is lost in the process and cannot be restored, although there are variations on the standard baseline JPEG that are lossless. There is also an interlaced"Progressive JPEG" format, in which data is compressed in multiple passes of progressively higher detail. This is ideal for large images that will be displayed while downloading over a slow connection, allowing a reasonable preview after receiving only a portion of the data. However, progressive JPEGs are not as widely supported.

The file format is known as 'JPEG Interchange Format' (JIF), as specified in Annex B of the standard. However, this "pure" file format is rarely used, primarily because of the difficulty of programming encoders / decoders that fully implement all aspects of the standard and because of certain shortcomings of the standard:

• Color Space definition
• Component Sub-Sampling Registration definition
• Pixel Aspect Ratio definition

A couple of additional standards have evolved to address these issues. The first of these, released in 1992, was JPEG File Interchange Format (or JFIF), followed in recent years by Exchangeable image file format (Exif) and ICC color profiles.

There is some confusion between the original 'JPEG Interchange Format' (JIF) and the similarly titled 'JPEG File Interchange Format' (JFIF). In some ways JFIF is a cutdown version of the JIF standard in that it specifies certain constraints (such as standard color space), while in other ways it is an extension of JIF due to the standard Application Segment header. The documentation for the original JFIF standard states:

JPEG File Interchange Format is a minimal file format which enables JPEG bitstreams to be exchanged between a wide variety of platforms and applications. This minimal format does not include any of the advanced features found in the TIFF JPEG specification or any application specific file format. Nor should it, for the only purpose of this simplified format is to allow the exchange of JPEG compressed images. ^[1]

[http://en.wikipedia.org/wiki/JPEG]