8.3. Edge

8.3.1. Activating the filter

You can find this filter through FiltersEdge-DetectEdge….

8.3.2. Options

Figure 17.155. Edge filter options

Edge filter options

Presets, Preview, Split view
[Note] 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.