The JPEG2000 initiative was started with the goal to improve on the original JPEG standard with better compression algorithms. Ideally the concept was to offer lossless and lossy compression at the time of saving. Another key element in the development of the JPEG2000 format is getting away from using the DCT (Discrete Cosine Transform) compression algorithm to incorporating wavelet technology. The existing DCT-based algorithm divides images into separate blocks that are visible in decompressed JPEG images saved with high compression. Wavelet technology however stores its information in a data stream, instead of storing blocks of image data, avoiding the blockiness common in highly compressed JPEG images.
The original JPEG2000 proposal was on the 7th WG1 in Geneva in February 1996, this is when the name "JPEG2000" first appeared. On the 10th WG1 meeting in Dijon in March 1997, there was a call for contribution issued. On the 12th WG1 meeting in Sydney in November 1997, there were 24 complete and 5 partial algorithms presented.
The Wavelet/TCQ proposal performed the best in the overall rankings. Finally in March 1998 the first prototype algorithm for JPEG2000 was implemented. The latest JPEG2000 algorithm is VM 5.2.
As mentioned in the introduction, JPEG2000 incorporates wavelet technology rather than the DCT compression algorithm. A wavelet image coding system based on transform coding consists of the following modules:
* Image preparation
* Two-dimensional image transformation
* Block-coding + Entropy coding
* Packetizing / File format preparation
Before we go on, I will explain the difference between lossy and lossless compression as these terms will be used throughout the rest of the essay.
Lossless and Lossy Compression
Lossless and lossy compression are terms that describe whether or not, in the compression of a file, all original data can be recovered...