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Re: connected component labeling problem in a graylevel image without background [message #32538 is a reply to message #32470]

Wed, 16 October 2002 09:22

Jaco van Gorkom
Messages: 97
Registered: November 2000

Member

"Julia" <julia65201@yahoo.com> wrote in message news:aok20m$efp$1@dipsy.missouri.edu...
> ...
> I tested the algorithm on a 1730*2210 image with 364 gray levels. If I use
> the label_region in IDL to mask and relabel, it takes about 80s. While if I
> use the watershed algorithm tm_wshe1.pro, it takes more than 4000s.

Hello Julia,

for this size of image and number of gray levels, a fast solution is
probably not possible in IDL. I am aware of a routine by Harvey Rhody at
http://www.cis.rit.edu/class/simg782/ that does exactly what you want.
(hr_label_region, this was a tip from Jason on this newsgroup sometime.) It
loops over the elements of the image and is therefore not very fast, but
may be quite instructive.

If speed of this operation is really important to you, then you should
consider writing it in C as a dlm. Or, if you do not want to learn how to do
that, find someone to do it for you. And who knows, maybe RSI can be
convinced that this is the one feature that would make IDL complete?

Good luck,
Jaco

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[Message index]

		Re: connected component labeling problem in a graylevel image without background By: Karsten Rodenacker on Tue, 15 October 2002 00:52
		Re: connected component labeling problem in a graylevel image without background By: Jaco van Gorkom on Wed, 16 October 2002 09:22
		Re: connected component labeling problem in a graylevel image without background By: Julia on Wed, 16 October 2002 08:55

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