7.6. Sobel

7.6. Sobel
	7. 边缘侦测滤镜

7.6.1. Overview

图 17.148. Applying example of the Sobel filter

Original image

Filter “Sobel” applied

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.

7.6.2. Activating the filter

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

7.6.3. Options

图 17.149. Sobel filter options

Preview: If checked, changes in the image are displayed in the Preview in real time before being applied to the image.
Sobel horizontally: Renders near horizontal edges.
Sobel vertically: Renders near vertical edges.
Keep sign of result: This option allows you to set how the filter will work if you have selected one direction for use only: a flat relief with bumps and hollows will be created.