JPEG is a standard for coding/compression of still pictures. It is used in the CCTV systems to compress and store individual frames of video. JPEG was developed by the Joint Photographic Experts Group. This is short for Joint Photographic Experts Group international – a good and very popular standard for still images that is supported by many modern programs. With JPEG, decompression and viewing can be done from standard Web browsers.
JPEG compression can be done at different user-defined compression levels, which determine how much an image is to be compressed. The compression level selected is directly related to the image quality requested.
Besides the compression level, the image itself also has an impact on the resulting compression ratio. For example, a white wall may produce a relatively small image file (and a higher compression ratio), while the same compression level applied on a very complex and patterned scene will produce a larger file size, with a lower compression ratio.
JPEG2000
Another still image compression standard is JPEG2000, which was developed by the same group that also developed JPEG. Its main target is for use in medical applications and for still image photography. At low compression ratios, it performs similar to JPEG but at really high compression ratios it performs slightly better than JPEG. The downside is that support for JPEG2000 in Web browsers and image displaying and processing applications is still very limited. |