Adjusts (refines) the shape of area selections using a circular ‘brush’ [5]. Clicking inside the area
selection and dragging along its boundary will expand the boundary outwards. Clicking outside
the area selection and dragging along its boundary will shrink the boundary inwards. Once the
tool has been applied, ImageJ will treat the adjusted ROIs as Composite Selections. The brush
diameter can be adjusted by double clicking on the tool icon.