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Re: isolating lichens from the background

Posted by Charles R Parker on May 19, 2008; 3:25pm
URL: http://imagej.273.s1.nabble.com/isolating-lichens-from-the-background-tp3696183p3696186.html

Thank you for the suggestions. I will look into texture analysis and
neural networks.

Chuck
=========================
Charles R. Parker, Ph.D.
Research Aquatic Biologist
U. S. Geological Survey
1316 Cherokee Orchard Road
Gatlinburg, TN 37738

E-mail: [hidden email]
Phone: (865) 436-1704



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Re: isolating lichens from the background






 > I'm new to image processing and ImageJ, so please bear with me. I need
to
 > be able to measure the area of healthy and necrotic lichens in
 > photographs. Examples are at
http://dlia.org/images/Parker/ParkerTIFS.html
 >
 >  So far, I have not been able to isolate the lichen from the
background,
 > let alone measure anything. I would appreciate any suggestions anyone
may
 > have on a suitable approach.


An idea: perform texture analysis. The lichens look fairly homogeneous
texture-wise.

A very crude texture analysis: for a given circular ROI, determine by
whatever statistics (color, particle count, distance between local
maxima, ..., or a combination of them) whether it belongs to the lichen
or not. Then iterate the ROI over entire image, centered on each pixel,
so that you an create a mask: white for lichen pixels, black for
non-lichen pixels.

I am sure the literature has better ways to do it. This looks like the
kind of problem a neural network should be able to get trained for.

Hope that helps.

Albert

--
Albert Cardona
http://www.mcdb.ucla.edu/Research/Hartenstein/acardona