Comparison of JPEG2000 with JPEG
JPEG2000 is an image compression standard which is wavelet-based. There is a reasonable increase in the compression performance compared to JPEG. One of the notable benefits of JPEG2000 is the flexible nature of the codestream which are progressive and have high pixel accuracy. The codestream is obtained after the process of compression of a JPEG2000 image. This JPEG2000 image is scalable that is it has the ability to be decoded in many ways. One such method of encoding is to truncate the JPEG2000 image to obtain a lower resolution image. By arranging the codestream in different ways one can achieve a better performance. Thus it is clear that JPEG2000 requires a number of decoders/ encoders which are highly complex and have a high degree of computation involved in them. The next difference in JPEG2000 while compared to JPEG lies in visual artifacts. While the use of JPEG2000 results in ringing artifacts which are generally manifested as rings near the edges, JPEG results in blocking artifacts. JPEG2000 encodes metadata in XML form.
Features of JPEG2000
The compression performance depends on the bit rates. In case of high bit rates, the artifacts are imperceptible, so it has a minor fidelity advantage. But in case of low bit rates the advantage of JPEG2000 is enormous. Artifacts become almost invisible and blocking is avoided. These gains are because of the use of DWT technology. During the compression process, JPEG2000 image is decomposed to multiple resolutions. This is used for the purposes of image presentation other than compression. JPEG2000 images can be compressed by both lossy and lossless compression techniques. It also supports progressive transmission which is commonly known as progressive decoding or SNR scalability. Besides these there are other features such as error resilience, flexible file format and spatial info of the side channel.
Performance of JPEG2000
Applications which can get a better performance out of JPEG images are those containing large images and images which have low contrast near the edges such as medical images. JPEG2000 image has 20% better performance on compression when compared to JPEG.