Shrink node

Left Toolbar > Compose icon Compose Nodes > Shrink icon Shrink node

The Shrink node shrinks the bright areas of the image in X and Y. This tool works on the individual channels of the image. The channel value on a pixel is set to the minimum value on the region defined by radius x and radius y.

In0 Img

Image with a shrink filter of 5 x 5 pixels.