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From: msp@ukc.UUCP (M.S.Parsons)
Newsgroups: net.dcom,net.micro
Subject: Re: Squeezing files.
Message-ID: <5269@ukc.UUCP>
Date: Fri, 28-Jun-85 11:00:14 EDT
Article-I.D.: ukc.5269
Posted: Fri Jun 28 11:00:14 1985
Date-Received: Mon, 24-Jun-85 06:33:33 EDT
References: <1414@ecsvax.UUCP> <784@turtlevax.UUCP> <1861@ukma.UUCP> <789@turtlevax.UUCP>
Reply-To: msp@ukc.UUCP (Mike Parsons)
Organization: Computing Laboratory, U of Kent at Canterbury, UK
Lines: 18
Xref: watmath net.dcom:1052 net.micro:10861

In article <789@turtlevax.UUCP> ken@turtlevax.UUCP (Ken Turkowski) writes:
>>..
>>Lempel-Ziv doesn't do NEARLY that well.  We've been using it for
>>months, and we've found that text and program sources usually get about
>>55-65% compression, while binaries get about 45-55% compression.
>>..
>I can see that we have a semantic problem here.  By "image", I mean a
>picture, or two-dimensional signal.  By "binary", I mean ones and
>zeros, black and white, no grey-scale, no color.
>..
>I reiterate my claim of 90% average compression.
>..

I agree with Ken: compress works brilliantly with binary IMAGES. It is
certainly better than UCB compact. What's interesting is that it works 
well with the image as a raster, run-length or quadtree: the underlying 
structure seems to make little difference.
--Mike.