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From: Brendan <brendandetracey@yahoo.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: outer perimeter binary blobs - vectorisation
Date: Tue, 8 Sep 2009 06:10:08 -0700 (PDT)
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On Sep 8, 9:47 am, Brendan <brendandetra...@yahoo.com> wrote:
> I have a binary image with many (~2000) blobs. Each blob is separated
> by at least two pixels. The image has been despurred and cleaned with
> bwmorph and bwlabeled. I need to extract the outer perimeter(1 pixel
> width) of each blob and give it the same label as its blob. This is
> easily done by looping through the blobs, and taking the difference of
> the blob and the blob enlarged by one pixel. Easily done but very
> slow.
>
> The above would extract the 8-connected outer perimeter. How would I
> extract the 4-connected perimeter?
>
> Any suggestions to vectorise or otherwise speed up this operation?
>
> Thanks

Scratch the stupid 4-connected vs 8-connected perimeter question.
Suggestions on speed would still be appreciated.