Posted by
Straub, Volko A. (Dr.) on
Nov 13, 2015; 4:14pm
URL: http://imagej.273.s1.nabble.com/Automatically-detect-circular-ROI-tp5014946p5014947.html
Hi Maria,
Here is a suggestion that might work based on the sample image:
- convert image to 8-bit greyscale
- auto threshold image using triangle method
- carry out a binary open (if you follow this by a binary dilate, you can smooth the edges a bit more)
- invert the image
- use analyse particle (size: 1000-Infinity; circularity: 0.5-1)
- for the sample image, this produces a nice selection of the filter
- you can then easily obtain the centre of the selection (Measure Centroid) and use this to create a circular selection if that is needed
Hope this helps,
Volko
-----Original Message-----
From: ImageJ Interest Group [mailto:
[hidden email]] On Behalf Of MariaS
Sent: 13 November 2015 15:16
To:
[hidden email]
Subject: Automatically detect circular ROI
<
http://imagej.1557.x6.nabble.com/file/n5014946/petri_dish.jpg>
Dear everybody,
I am new to ImageJ and I am trying to automate the task of manually selecting a circular ROI.
I have this kind of images and I want everytime ImageJ to automatically detect the inside membrane, which is not exactly in the same position in every image. Then I want to Clear the Outside, so I can work on the region I am interested in. I tried with the plugin Hough Circles, but it doesn't really work; when I try to use it ImageJ crashes and I am not sure if it could give me the result I want, since I cannot use it.
It would be really helpful if somebody could give me some advice. Is there an available plugin which could perform this task?
Thank you in advance.
Maria
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