9.8. Erodér

9.8.1. Oversyn

Figur 17.186. Applying example for the Erode filter

Applying example for the Erode filter

Originalbiletet

Applying example for the Erode filter

Filter «Erode» applied


Dette filteret utvider og forsterkar mørke område i det aktive laget eller det aktive utvalet.

For every image pixel, it brings the pixel Value (luminosity) into line with the lowest Value (the darkest) of the 8 neighboring pixels (3×3 matrix). So, a dark pixel is added around dark areas. An isolated pixel on a brighter background will be changed to a big «pixel», composed of 9 pixels, and that will create some noise in the image.

In this image, the studied pixel has a red border and the studied 3×3 matrix has a green border. Thus when the pixel marked with «I» is inside the green border, the studied pixel turns to black.

A larger dark area will expand by one pixel in all directions:

På dette biletet er filteret køyrd tre gonger.

On more complex images, dark areas are widened and enhanced the same, and somewhat pixelated. Here, the filter was applied 3 times:

Dersom bakgrunnen er mørkare enn forgrunnen, vil filteret sjølvsagt dekke heile biletet.

9.8.2. Activating the Filter

This filter is found in the main menu under FiltersGenericErode.

9.8.3. Eksempel

Figur 17.187. Erode text

Erode text