^^

This demonstration shows the comparison between JPEG2000 encoding and 'conventional' JPEG encoding. Unlike some demonstrations you may see however, it tries to do this as fairly as possible.
With conventional JPEG encoding, applying too much compression will cause very undesirable artefacts, such as harsh boundaries between different areas of colour, visible blocks, and fringes around edges.
Rather than compress so hard, a good way to reducing these artefacts is to reduce the overall image size before compressing it - the easiest thing to do is to halve it in both dimensions. JPEG compression then has to be far less abrupt to get to the same target file size - providing the image can then be enlarged up again to the original size. This works particularly well if the resulting image uses interpolation rather than replication to put back the missing pixels!

The following screens allow you to compare parts of several high quality test images to compare the effect of fairly severe amounts of JPEG and JPEG2000 compression. You will need a later version of a browser, capable of supporting embedded PNG. We recommend Netscape Communicator V4.7. All images are transmitted as PNG to avoid further distortion. Please note that the full size images vary from 200 Kbytes to over 2 Mbytes in size, before you start to look at them!