Path: utzoo!attcan!uunet!dino!sharkey!itivax!umich!zip!spencer
From: spencer@eecs.umich.edu (Spencer W. Thomas)
Newsgroups: comp.graphics
Subject: Re: SigGraph Fractal Compression
Message-ID: 
Date: 15 Aug 89 03:16:43 GMT
References: <444@mit-amt.MEDIA.MIT.EDU> <20400001@inmet>
	
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In-reply-to: sarrel@sioux.cis.ohio-state.edu's message of 14 Aug 89 14:56:26 GMT

The technique is valid, but it is not lossless.  In other words, what
you get out ain't what you put in.  For a noisy image (i.e., a
digitized image), this may be ok.  For other images (i.e., a computer
generated image with an alpha channel), this is not good at all.
Finally, compression is SLOW.  I recall hearing a figure of 1 hour per
image to compress (I could be wrong).  Thus, the technique is only
really useful if you are going to decompress much more frequently than
you will compress.

In these respects, it is very similar to another compression technique
that promises extremely high compression ratios (100:1 and better):
vector quantization.  VQ is slow to compress, fast to decompress, and
lossy.

In other words, TANSTAAFL.

--
=Spencer (spencer@eecs.umich.edu)