| Path: | icdoc!mvax.cc.ic.ac.uk!sunb!dds |
| From: | dds@sunb.cc.ic.ac.uk (Diomidis Spinellis) |
| Newsgroups: | comp.graphics |
| Subject: | Re: Compression of multi-bit images |
| Keywords: | delta modulation compression |
| Message-ID: | <1990Jun6.215749.21647@cc.ic.ac.uk> |
| Date: | 6 Jun 90 21:57:49 GMT |
| References: | <8099@b11.ingr.com> <SPENCER.90Jun4170821@spline.eecs.umich.edu> |
| Sender: | news@cc.ic.ac.uk (USENET News System) |
| Reply-To: | dds@cc.ic.ac.uk (Diomidis Spinellis) |
| Organization: | Imperial College Computer Center, London, UK |
| Lines: | 30 |
| Content-Length: | 1135 |
In article <SPENCER.90Jun4170821@spline.eecs.umich.edu> spencer@eecs.umich.edu (Spencer W. Thomas) writes: >Lossless methods: >A popular method is LZW (Lempel-Ziv-Welch) as found in the Unix 'compress' >program. [...] > >Simple Huffman (adaptive or otherwise (the Unix 'pack' program) may do [...] Some time ago I implemented a compress / uncompress set of programs for a face server project that was going on here, based on delta modulation. The compressed file contains the difference of each byte from the previous one, coded in a single nibble. I tried the delta modulation programs, compress and pack on a 256 * 256 * 8 gray scale picture of me. These are the results: Original 65536 /bin/pack 59660 /usr/ucb/compress 53510 ../deltac 40489 I can post the programs if there is demand. Diomidis -- Diomidis Spinellis Internet: dds@cc.ic.ac.uk Department of Computing UUCP: ...!ukc!iccc!dds Imperial College JANET: dds@uk.ac.ic.cc London SW7 2BZ #include "/dev/tty"
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