For Sample Radius, enter a pixel value between 1 and
100, and click OK.
For each pixel in the selection, Photoshop examines the
pixels around it, to the distance you specify in the radius setting.
If more than half of these surrounding pixels are selected, the
pixel remains in the selection, and the unselected pixels around
it are added to the selection. If less than half the surrounding
pixels are selected, the pixel is removed from the selection. The
overall effect is to reduce patchiness and smooth sharp corners
and jagged lines in the selection.
