limit to threshold in RGB image does not affect area?

[ard]

Measuring a thresholded grey image shows a reduction in area (and in mean) when the upper threshold value is lowered and a smaller portion of the image is shown in red.

An RGB image on thresholded on the other hand only shows a change in mean, not in area. Measuring 10x10 pixel ROI will always show area result of 100 pixels regardless of the number of pixels within the ROI shown in red as limited by threshold.
Is "limit to threshold" expected to NOT influence the area result when measuring an RGB color image (1.45d/1.46j) despite being checked in Set Measurement?

Ard
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[Michael Schmid]

Hi Ard,

Color thresholding is still in the 'experimental' status (also the title of the panel says so) and not fully integrated into ImageJ.
Apart form being ignored in 'limit to threshold', there are more problems with it; including the possibility of inadvertently overwriting the image...

Michael
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On Apr 6, 2012, at 12:33, A. Jonker wrote:

> Measuring a thresholded grey image shows a reduction in area (and in mean) when the upper threshold value is lowered and a smaller portion of the image is shown in red.
>
> An RGB image on thresholded on the other hand only shows a change in mean, not in area. Measuring 10x10 pixel ROI will always show area result of 100 pixels regardless of the number of pixels within the ROI shown in red as limited by threshold.
> Is "limit to threshold" expected to NOT influence the area result when measuring an RGB color image (1.45d/1.46j) despite being checked in Set Measurement?
>
> Ard