
Home > Terms > English, UK (UE) > Sub band coding
Sub band coding
Sub-band coding for images has roots in work done in the 1950s by Bedford and on Mixed Highs image compression done by Kretzmer in 1954. Schreiber and Buckley explored general two channel coding of still pictures where the low spatial frequency channel was coarsely sampled and finely quantized and the high spatial frequency channel was finely sampled and coarsely quantized. More recently, Karlsson and Vetterli have extended this to multiple subbands. Adelson et al. have shown how a recursive subdivision called a pyramid decomposition can be used both for compression and other useful image processing tasks. A pure sub-band coder performs a set of filtering operations on an image to divide it into spectral components. Usually, the result of the analysis phase is a set of sub-images, each of which represents some region in spatial or spatio-temporal frequency space. For example, in a still image, there might be a small sub-image that represents the low-frequency components of the input picture that is directly viewable as either a minified or blurred copy of the original. To this are added successively higher spectral bands that contain the edge information necessary to reproduce the original sharpness of the original at successively larger scales. As with DCT coder, to which it is related, much of the image energy is concentrated in the lowest frequency band. For equal visual quality, each band need not be represented with the same signal-to-noise ratio; this is the basis for sub-band coder compression. In many coders, some bands are eliminated entirely, and others are often compressed with a vector or lattice quantizer. Succeedingly higher frequency bands are more coarsely quantized, analogous to the truncation of the high frequency coefficients of the DCT. A sub-band decomposition can be the intraframe coder in a predictive loop, thus minimising the basic distinctions between DCT-based hybrid coders and their alternatives.
- Part of Speech: noun
- Synonym(s):
- Blossary:
- Industry/Domain: Entertainment
- Category: Video
- Company: Tektronix
- Product:
- Acronym-Abbreviation:
Other Languages:
Member comments
Terms in the News
Featured Terms
phylum placozoa
Macroscopic, flattened marine animals, composed of ventral and dorsal epithelial layers enclosing ...
phylum cnidaria
Cnidarians. Hydras, hydroids, jellyfish, sea anemones, and corals. Free-swimming or sessile, with ...
share a term with millions
Share a term with millions of users around the world and increase your online visibility.Share a ...
oak
Genus native to the Northern Hemisphere with spirally arranged leaves, catkins for flowers and ...
Everest
The last but not least mount Everest. The Earth's highest mountain, with a peak at 8,848 metres ...
aglaonema
Genus of about 20 species of usually rhizomatous, evergreen perennials from tropical forest in Asia. ...
Robojelly
Robojelly is a hydrogen-powered robot desgined in the United States that moves through the water ...
Ferdinand Porsche
Ferdinand Porsche (3 September 1875 – 30 January 1951) was an Austrian-German automotive engineer ...
Marzieh Afkham
Marzieh Afkham, who is the country’s first foreign ministry spokeswoman, will head a mission in east ...
define1
Share a term with millions of users around the world and increase your online visibility.Share a ...
Contributor
Featured blossaries
Browers Terms By Category
- Body language(129)
- Corporate communications(66)
- Oral communication(29)
- Technical writing(13)
- Postal communication(8)
- Written communication(6)
Communication(251) Terms
- Action toys(4)
- Skill toys(3)
- Animals & stuffed toys(2)
- Educational toys(1)
- Baby toys(1)
Toys and games(11) Terms
- Clock(712)
- Calendar(26)
Chronometry(738) Terms
- SAT vocabulary(5103)
- Colleges & universities(425)
- Teaching(386)
- General education(351)
- Higher education(285)
- Knowledge(126)
Education(6837) Terms
- Satellites(455)
- Space flight(332)
- Control systems(178)
- Space shuttle(72)