Re: Wand Tool mode for thresholded image

Posted by Michael Schmid on Jul 29, 2014; 8:29am
URL: http://imagej.273.s1.nabble.com/Wand-Tool-mode-for-thresholded-image-tp5008918p5008925.html

Hi Neil,

the Wand uses the mode set in its preferences (legacy, 4-connected, 8-connected) also for thresholded images.

You will easily see the difference between 4-connected and 8-connected when selecting a one-pixel wide line running at an arbitrary angle (not along x or y). You also see the difference when two particles are barely touching such that the closest pixels only have one common corner point.

The 'legacy' mode usually behaves like 8-connected (there may be exceptions; I don't remember exactly - it's a long time since I worked on this). You can see the difference between 8-connected and legacy if you have a particle with an inner hole: Click at the left side of the inner hole, "8-connected" will select the particle including the hole, "legacy" will select the hole (non-thresholded area).

As far as I can say, "Analyze Particles" is always 8-connected.


Michael
________________________________________________________________
On Jul 29, 2014, at 00:11, Neil Fazel wrote:

> If I use the Wand Tool on a thresholded image, which Mode (legacy, 4-connected, 8-connected) is used by default? I changed the Wand Tool mode for a thresholded image, but the contour drawn didn't seem to change, so I thought maybe it's being ignored. (I know that the Tolerance field is ignored when the image is thresholded.)
>
> Thanks,
> Neil

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