Re: Local Thresholding defined by a binary mask

Posted by Gabriel Landini on Mar 24, 2014; 1:45pm
URL: http://imagej.273.s1.nabble.com/Local-Thresholding-defined-by-a-binary-mask-tp5007063p5007065.html

On Monday 24 Mar 2014 14:00:50 you wrote:
> is there a plugin which allows me to use the threshold methods locally
> whereas the locations are defined by a binary mask? The Auto Local
> Threshold plugin seems not allow something like this.

With the original Auto Threshold plugin (in my page), you can "ignore black"
and/or "ignore white".
So (here I am assuming that you want to segment bright regions) you could add
1 to your image (no black=0 pixels now), paint in black all the regions you do
not want to influence the thresholding and apply the plugin with "ignore
black". That is a global threshold based on the histogram of the non-black
pixels.

The Auto Local Threshold is different. It uses circular masks to decide every
central pixel based on the local properties in the mask. Since a few of the
local methods are not histogram-based, you will have to modify each method to
ignore pixels masked by an another bitmap.

Cheers

Gabriel

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