Re: Counting Barnacles on a panel

Posted by David Webster on Nov 03, 2009; 2:22am
URL: http://imagej.273.s1.nabble.com/Counting-Barnacles-on-a-panel-tp3690575p3690577.html

You probably need to do something like Process/Binary/Outline to get just
the boundary pixels before the HT. Another possibility is to do a Watershed
segmentation if the "circles" are touching.

David Webster

On Mon, Nov 2, 2009 at 5:07 PM, Robert Dougherty <[hidden email]> wrote:

> Emiliano,
>
> I think this is a job for the Hough transform.  A way to start is to
> subtract the background, convert to 32-bit, find edges, and do an "adjust
> threshold" with limits of something like 175-743.  Now the little varmints
> are represented by reasonably well defined circles and arcs.  This should be
> perfect for the Hough transform.  The only Hough transform plugin that I've
> found so far is Hough Circles, and I can't seem to get it to work well in
> this case.  Also, the Hough Circles link is missing from the Plugins page.
> Perhaps someone else on the list knows how to drive it or knows of a more
> suitable plugin.  This is a rather basic capability that ImageJ should have
> if it does not.
>
> Bob
>
>
> On Oct 29, 2009, at 7:24 AM, Emiliano Pinori wrote:
>
> Hi,
>> I'm working on antifouling marine paints and had lots of panels to
>> analyze.
>> I found ImageJ a very helpfull tool. Anyway when it cames to the more
>> adult
>> and close togheter barnacles individuals on my panels i had experienced
>> some
>> difficoults in using my very simple macro to count for Barnacle at the ROI
>> area.
>> I use a subtcract background, followed by set scale, rectangular selection
>> find maxima within tollerance, and finally analyze Particles.
>>
>> Now the problem is that I will lose a lot of adult barnacles in my results
>> becouse they will never become not even 0.5 circular after find maxima due
>> to the close presence of ather smaller barnacle. Or becouse the edge do
>> not
>> are at the same brightness all over the preimeter. How can i improve the
>> accurancy without having too much false positives?
>>
>> I don´think I asked my question in a understandable way, so i put a photo
>> of
>> wath i have to analyze and hope someone understand me anyway.
>>
>> I need counts and area to have a % difference between Prov and Control
>> side
>> (just a 9 square cm ROI of each side)
>>
>> http://s943.photobucket.com/albums/ad273/zapatainsvezia/Barnacles%20Exemp/
>>
>> thank you Emiliano Pinori
>> Ph.D. student
>> Gothemburg University (Sweden)
>> --
>> View this message in context:
>> http://n2.nabble.com/Counting-Barnacles-on-a-panel-tp3912808p3912808.html
>> Sent from the ImageJ mailing list archive at Nabble.com.
>>
>
> Robert Dougherty, Ph.D.
> President, OptiNav, Inc.
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> Redmond, WA 98052
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