Questo filtro amplifica e mette in risalto le aree chiare del livello o della selezione correnti.
For every image pixel, it brings the pixel Value (luminosity) into line with the upper value (the brightest) of the 8 neighboring pixels (3×3 matrix). So, a bright pixel is added around bright areas. An isolated pixel on a brighter background will be deleted. A larger bright area will dilate by one pixel in all directions.
On complex images, bright areas are widened and enhanced the same, and somewhat pixelated.
Su uno sfondo in tinta unita, questo filtro è in grado di togliere i disturbi: