[comp.graphics] IFS Compression of Graphics Images

ahg@k.cc.purdue.edu (Allen Braunsdorf) (01/16/88)

A few days ago I read:

	Barnsley, M. F. and A. D. Sloan.
	"A Better Way to Compress Images."
	Byte, volume 13 number 1, January 1988, pp. 215-223.

After thinking about the algorithm for a while, I wrote a C version of the
program listed in the article and tried out the given data sets.  I now have
no doubt that it works, but I'd like more information on the subject of IFS
encoding.

For those who have not read the article, I suggest you take a look at it.
They show a few example images (in color- they don't discuss color in the
article) that they compressed and their size after compression.  These range
from 100-2000 bytes for detailed color pictures.

BTW, I believe that the caption for Figure 4 is incorrect.  I am reasonably
sure that the seascape took 60 transformations and >1000< rather than >100<
bytes.  (Some quick calculations lead me to believe that their encoding yields
16 bytes per transform plus some overhead for global information.)

If anybody wants the program or data (all short and device independent (uses
UNIX(tm) plot library)), I can post or mail them.

Any information on this or related subjects would be greatly appreciated, as
would more data sets to try out.

Allen Braunsdorf			WORK	k.cc.purdue.edu!ahg
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