8.3. Edge

8.3.1. Activating the filter

You can find this filter through Filters → Edge-Detect → Edge….

8.3.2. Options

Figure 17.166. Edge filter options

Presets, “Input Type”, Clipping, Blending Options, Preview, Split view

	Note
	These options are described in Section 2, “Common Features”.

Algorithm

Edge detector offers several detection methods:

• Sobel

  Here, this method has no options and so is less interesting than the specific Sobel.

  

  After applying the filter (Sobel option)

  Prewitt compass

  Result doesn’t look different from Sobel.

  

  After applying the filter (Prewitt compass option)

  Gradient

  Edges are thinner, less contrasted and more blurred than Sobel.

  

  After applying the filter (Gradient option)

  Roberts

  No evident difference from Sobel.

  

  After applying the filter (Roberts option)

  Differential

  Edges less bright.

  

  After applying the filter (Differential option)

  Laplace

  Less interesting than the specific one.

  

  After applying the filter (Laplace option)

Amount

A low value results in black, high-contrasted image with thin edges. A high value results in thick edges with low contrast and many colors in dark areas.

Border behavior

Where the edge detector will get adjoining pixels for its calculations when it is working on the image boundaries. This option will only have an effect on the boundaries of the result (if any). Clamp is the default and the best choice.