User Guide

GNU Image Manipulation Program
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15.5.5.2 Activating the filter
You can find this filter through Filters → Edge Detect → Neon....
15.5.5.3 Options
Figure 15.87: Neon filter options
Radius This option lets you determine how wide the detected edge will be.
Amount This option lets you determine how strong the filter effect will be.
15.5.6 Sobel
15.5.6.1 Overview
Figure 15.88: Applying example of the Sobel filter
(a) Original image (b) Filter Sobel applied
You can find this filter through Filters → Edge detect → Sobel.
Sobel’s filter detects horizontal and vertical edges separately on a scaled image. Color images are turned into RGB scaled images.
As with the Laplace filter, the result is a transparent image with black lines and some rest of colors.