In the mid 1980s joint work by the members of the ITU-T (International Telecommunication Union) and the ISO (International Standards Organisation) led to standardisation for the compression of grey scale and colour still images. This effort was then known as JPEG: the Joint Photographic Experts Group. As is apparent, the word joint refers to the collaboration between the ITU-T and ISO. The JPEG encoder is capable of coding full colour images at an average compression ratio of 15 : 1 for subjectively transparent quality. Its design meets special constraints, which make the standard very flexible. For example, the JPEG encoder is parametrisable, so that the desired compression/quality trade-offs can be determined based on the application or the wishes of the user.

Inspec keywords: ISO standards; image coding; image colour analysis; encoding; data compression; codecs

Other keywords: advanced video coding; ITU-T; image compression; International Telecommunication Union; picture coding; International Standard Organisation; JPEG2000; Joint Photographic Experts Group; colour image; standard codec; encoder; ISO

Subjects: Image and video coding