Flood filling an interval of grey values

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Flood filling an interval of grey values

Stein Rørvik
The flood fill tool fills any connected regions having the exact same greyscale pixel value as the source pixel.

Is there any plugin or tool that does the same, but instead fills adjacent pixels having values within a certain threshold?
That is, if the source pixel has value say 50, any connected regions with a value between say 45 and 55 would be filled.
I need this both for 2D and 3D; but 2D is most important.

In the old NIH Image for Mac classic OS, you could do this quite easily by setting an upper and lower threshold, and then flood filling from a point within the thresholded region while the threshold is active. Then all connected pixels within the threshold would be flood filled.

Stein

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Re: Flood filling an interval of grey values

Wayne Rasband-2
> On Feb 17, 2017, at 4:53 AM, Stein Rørvik <[hidden email]> wrote:
>
> The flood fill tool fills any connected regions having the exact same greyscale pixel value as the source pixel.
>
> Is there any plugin or tool that does the same, but instead fills adjacent pixels having values within a certain threshold?
> That is, if the source pixel has value say 50, any connected regions with a value between say 45 and 55 would be filled.
> I need this both for 2D and 3D; but 2D is most important.
>
> In the old NIH Image for Mac classic OS, you could do this quite easily by setting an upper and lower threshold, and then flood filling from a point within the thresholded region while the threshold is active. Then all connected pixels within the threshold would be flood filled.

You can use the changeValues() macro function. For example, changeValues(45,55,0) changes all pixels with values between 45 and 55 to 0.

-wayne

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Re: Flood filling an interval of grey values

Michael Schmid-3
In reply to this post by Stein Rørvik
Hi Stein,

you can use the Wand Tool to select an area with the initial pixel value
(where the click was) plus/minus some tolerance. Double-click the Wand
Tool to set the tolerance.
Then fill the selected area by Edit>Fill (simply type 'f' or ctrl-f) or
Process>Math>Set.

In contrast to the changeValues macro function mentioned by Wayne, this
only affects connected pixels (the Wand options allow you to select
4-connected or 8-connected).

For 3D, there is a 3D Wand with adaptive (automatic) tolerance at
   http://yawi3d.sourceforge.net/
but I have no experience with it, and I don't know whether it is
possible to create stack slice selections with it.

Michael
________________________________________________________________


On 2017-02-17 10:53, Stein Rørvik wrote:

> The flood fill tool fills any connected regions having the exact same
> greyscale pixel value as the source pixel.
>
> Is there any plugin or tool that does the same, but instead fills
> adjacent pixels having values within a certain threshold?
> That is, if the source pixel has value say 50, any connected regions
> with a value between say 45 and 55 would be filled.
> I need this both for 2D and 3D; but 2D is most important.
>
> In the old NIH Image for Mac classic OS, you could do this quite
> easily by setting an upper and lower threshold, and then flood filling
> from a point within the thresholded region while the threshold is
> active. Then all connected pixels within the threshold would be flood
> filled.
>
> Stein

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