Multiple ROIs with Selection Brush Tool

Hi All -

I am having what seems like such a basic problem, but I can’t crack it!
I am using the Selection Brush Tool to generate ROIs and have no problem making the first one and saving it, but when I go to make the second ROI, the tool will not work. It’s still selected but when I click on the image the yellow circle appears and disappears without allowing me to ‘brush’ over any pixels. It’s as if the previous ROI is not closed or completed in some way, the turquoise line around ROI 1 flashes dark blue when I try, but it doesn’t seem to matter what I do, it won’t allow me to make a second ROI.

Please help!!


Hi and welcome to the forum!

Does your first ROI still exist on the image when you try to draw the second one? The brush tool is aimed at modifying an existing ROI: If you start drawing in the background and then sweep over your ROI, it will remove that area. And if you start drawing inside the ROI it will add new area. It won’t draw a new ROI in another region (unless you force it to with “Shift” key but I think that’s not what you aim for here).

Do you want to draw a second independent ROI? Then save the first ROI first. For example add it to the ROI manager (shortcut: T). Afterwards delete it: Edit > Selection > Select None (Shortcut Shift+A). Then start drawing your second ROI. Add it to the ROI manager once finished etc.
If you want to see the ROIs that you have already drawn and are now stored in the ROI manager as overlay, simply check the “show all” box in the manager.

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