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> Daubechies studied different types of wavelets, which are now an essential part of image compression formats like JPEG. Minor correction but the discrete wav
by joefourier 6y ago
> Daubechies studied different types of wavelets, which are now an essential part of image compression formats like JPEG.
Minor correction but the discrete wavelet transform based on Daubechies' work is used in JPEG2000, not JPEG, which uses the discrete cosine transform (other codecs generally use related integer approximations). JPEG2000 never managed to gain much popularity outside of digital cinema (e.g. Red RAW, Cineform, and I believe delivery codecs for cinemas). Which is a shame, given that wavelets have superior properties for multi-resolution decomposition.
- jacobolus 6y agoJPEG-2000 and another wavelet-based codec MrSID https://en.wikipedia.org/wiki/MrSID https://en.wikipedia.org/wiki/MrSID are used for archival storage of high-resolution scans, e.g. by the Library of Congress http://memory.loc.gov/ammem/help/compression.html http://memory.loc.gov/ammem/help/compression.html JPEG has the big advantages that it is built in to web browsers, can be decoded effectively on less powerful hardware, and is “good enough” for most typical uses.