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Re: Wand Tool mode for thresholded image

Posted by Michael Schmid on Jul 29, 2014; 8:37am
URL: http://imagej.273.s1.nabble.com/Wand-Tool-mode-for-thresholded-image-tp5008918p5008926.html

Hi Neil,

you have encountered a common problem for 16-bit and float (32-bit) images:

When thresholding, the 'red' display is based on updating the 8-bit LUT, thus it has only 8 bits accuracy. The Wand uses the exact pixel values (full accuracy), so you will see a difference between the display and the selection of the Wand.

The way out would be completely rewriting how the threshold is displayed.  Unfortunately, this goes rather deep into the basic structure of ImageJ (ImageProcessor level), it would be a lot of work.  I thought about it for a while, but there is a very problem that it could break existing plugins or macros.  So I fear that you have to live with this problem.

Michael
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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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