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Re: Getting more information on ImageJ algorithms

Posted by Gabriel Landini on Nov 24, 2013; 9:09pm
URL: http://imagej.273.s1.nabble.com/Getting-more-information-on-ImageJ-algorithms-tp5005673p5005684.html

On Sunday 24 Nov 2013 20:36:17 Adam Hughes wrote:
> me as I'm very inexperience, but how would one actually make the "Try All"
> call shown in the threshold tutorial?  

Did you follow the "Installation" instructions in the tutorial link?
It is very clearly explained there .

I think Wayne since recently includes the Auto Local Threshold command in the
default IJ download. If so, you might get an error of a duplicate command
after installing the auto_threshold.jar file and you may need to find the old
"Auto Local Threshold" class file  in the plugins folder and delete it.

> GUI, but imagine I'd actually have to run some code as a macro to get this
> montage of all the various thresholds, right?

No, it is the default option of Image>Adjust>Auto Threshold and
Image>Adjust>Auto Local Threshold.

> words, it considers a particle as anything connected by black pixels, and
> everyting that's encompassed in such a perimeter is counted as that
> particle?

You will have 3 ways of thresholding an image
1. Image>Adjust>Threshold is IJs applet. It does not have Try all.
The "dark background" option allows to select bright regions

2. Image>Adjust>Auto Threshold  
3. Image>Adjust>Auto Local Threshold

are similar, have "try all" and "white particles" switch allows to choose
bright regions. For these 2 commands. the result is a binary image. Command 2.
allows processing true 16 bit images.

Please read thoroughly:
http://www.dentistry.bham.ac.uk/landinig/software/autothreshold/autothreshold.html
All your questions should be answered there.

Cheers

Gabriel

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