Re: Repost of Vertex question...

[Struan Gray <struan.gray(at)sljus.lu.se>]

Craig Markwardt, craigmnet@cow.physics.wisc.edu writes:
>Brian Koss <bakoss@rainbow.uchicago.edu> writes:
>> 
>> 	I have images of polygons connected edge to edge in a
>> quasiperiodic array, like the one I have attached to this
>> message... The images are black and white and the edges of
>> the polygons are distinguisable because they are straight
>> lines. I would love to be able to use IDL to find the
>> vertices in this image.
>
> Cute. Somehow I don't think this is a program that
> someone on the newsgroup can knock out in ten minutes.


    Oh.  I don't know.
   
    A quasicrystal will have a limited number of vertex
orientations, which you can pick out by hand.  Simply cut
out one of each type of vertex into it's own sub-image, do a
cross correlation between that and the whole image to find
where that type of vertex occurs, and add up the resulting
lists for each vertex type.

	Alternately, if you know something about the scale
invariance of the quasicrystal, find the postions of the
edges or centres of the polygons in the same way, and then
use the quasicrystal's scaling properties to find the
vertices.


Struan