2.4. Selective Gaussian Blur
| 2. 模糊滤镜 |

### 2.4. Selective Gaussian Blur

#### 2.4.1. Overview

图 17.11. The Selective Gaussian Blur filter

Original

Blur applied

Contrary to the other blur plug-ins, the Selective Gaussian Blur plug-in doesn't act on all pixels: blur is applied only if the difference between its value and the value of the surrounding pixels is less than a defined Delta value. So, contrasts are preserved because difference is high on contrast limits. It is used to blur a background so that the foreground subject will stand out better. This add a sense of depth to the image with only a single operation.

#### 2.4.2. Activate the filter

You can find this filter in the image menu under Filters → Blur → Selective Gaussian Blur

#### 2.4.3. Options

图 17.12. “Selective Gaussian” filter parameters settings

Blur radius

  Here you can set the blur intensity, in pixels.

Max. delta

  Here you can set the maximum difference (0-255) between the pixel value and the surrounding pixel values. Above this Delta, blur will not be applied to that pixel.

2.3. Gaussian Blur |  | 2.5. Motion Blur

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