7.3. Edge
| 7. Edge-Detect Filters |

### 7.3. Edge

#### 7.3.1. Overview

Figure 17.140. Applying example for the Edge filter

Original image

After applying the filter (Sobel option)

Figure 17.141. Applying examples for the Edge filter

After applying the filter (Prewitt compass option)

After applying the filter (Gradient option)

Figure 17.142. Applying example for the Edge filter

After applying the filter (Roberts option)

After applying the filter (Differential option)

Figure 17.143. Applying example for the Edge filter

After applying the filter (Laplace option)

#### 7.3.2. Activating the filter

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

#### 7.3.3. Options

Figure 17.144. Edge filter options

Algorithm

  Edge detector offers several detection methods:

  Sobel

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

  Prewitt compass

    Result doesn't look different from Sobel.

  Gradient

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

  Roberts

    No evident difference from Sobel.

  Differential

    Edges less bright.

  Laplace

    Less interesting than the specific one.

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.

Wrap, Smear, Black

  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). Smear is the default and the best choice.

7.2. Difference of Gaussians |  | 7.4. Laplace

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