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- Newsgroups: comp.compression
- Path: sparky!uunet!comp.vuw.ac.nz!canterbury.ac.nz!cantua!hugh
- From: hugh@cantua.canterbury.ac.nz (Hugh Emberson)
- Subject: Re: bitmap compression
- Message-ID: <BxA7y2.7HB@cantua.canterbury.ac.nz>
- Nntp-Posting-Host: cantua.canterbury.ac.nz
- Organization: University of Canterbury, Christchurch, New Zealand.
- References: <Bx9C19.4r2@ccu.umanitoba.ca>
- Date: Fri, 6 Nov 1992 06:42:01 GMT
- Lines: 47
-
- In article <Bx9C19.4r2@ccu.umanitoba.ca>, umfehr06@ccu.umanitoba.ca (John Fehr) writes:
- > I'm currently looking for compression algorithms to compress weather charts.
- > These charts contain about 95% white pixels, and 5% black pixels. I've
- > already thought of using GIF, but the files only shrink down to ~100k.
- > (Originally ~1meg uncompressed.) I've also thought of using arithmetic
- > coding. Does anyone have any suggestions as to other compression methods?
-
- You could try Group 4 fax, but I wouldn't expect it to be much better than GIF.
-
- Probably the best method would be an arithmetic encoder with a template model.
- Have a look in:
-
- @article{Langdon81,
- author = {Glen G. Langdon, Jr. and Jorma Rissanen},
- journal = {IEEE Transactions on Communications},
- month = jun,
- number = {6},
- pages = {858--867},
- title = {{C}ompression of {B}lack--{W}hite {I}mages with
- {A}rithmetic {C}oding},
- volume = {COM-29},
- year = {1981}
- }
-
-
- and:
-
-
- @inproceedings{Moffat91,
- author = {Alistair Moffat},
- address = {Los Alamitos, California},
- booktitle = {{P}roceedings of the {D}ata {C}ompression {C}onference 1991},
- editor = {James A. Storer and J.H. Reif},
- pages = {382--391},
- publisher = {{IEEE} {C}omputer {S}ociety {P}ress},
- title = {{T}wo level context based compression of binary images},
- year = {1991}
- }
-
- [The above is in BibTeX format, just strip out the {braces} to read it.]
-
- I understand that this method is/will be used in the JBIG standard. It is
- very good and very simple.
-
-
-
- Hugh
-