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From: miller@unicom.UUCP (Gregory S Miller)
Newsgroups: comp.lang.c,comp.lang.lisp,comp.ai
Subject: Need help with finding perimeters of bounded areas
Keywords: area, bounded, pos/neg images
Message-ID: <135@unicom.UUCP>
Date: 12 Oct 89 02:37:36 GMT
Distribution: usa
Organization: Science Computer Center, College of Marin, Kentfield CA
Lines: 27



Consider an area A on an euclidean plane surface.  Inside A 
are an arbitrary number of lines that "fill out" A.  That is,
A is defined not by a perimeter, but rather as a filled object (
negative versus positive images...).

Now each line has a diameter D(i) where i is an subscript telling 
which line we`re referring.  It is perfectly reasonable that the lines
may overlap.  Since they overlap, one could use a lot of lines with
small diameters or a smaller number with larger diameters and still
produce the same area A.

Problem: Given the area A, find the perimeter - eliminate all lines
	 inside A and leave just the outline.  A is "given" by a
	 list of vectors with a diameter (ie. start/end point with
	 diameter). 

	 Just in case it was not already clear, the number, location
	 and diameter (D(i)) of each line is arbitrary so long as
	 the area A is filled out.

I do not know quite where to start on this problem.  I`ve never
run across "standard algorithms" which would be suited to this problem.

Ideas, text references, or the like would be helpful.
Thanks.