User Guide

GNU Image Manipulation Program
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You can find this filter through Filters → Generic → Erode
This filter widens and enhances bright areas of the active layer or selection.
For every image pixel, it brings the pixel Value (luminosity) into line with the upper Value (the brightest) of the 8 neighbouring
pixels (3x3 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 pixellated.
On a solid background, this filter can delete noise:
15.8 Glass Effects Filters
15.8.1 Introduction
Glass Effects filters result in an image as if it were seen through a lens or glass tiles.
15.8.2 Apply Lens
15.8.2.1 Overview
Figure 15.110: The same image, before and after applying lens effect.
(a) (b)
You can find this filter through Filters → Glass effects → Apply Lens
After applying this filter, a part of the image is rendered as through a spherical lens.