4.7. Symmetric Nearest Neighbor
| 4. 增强滤镜 |

### 4.7. Symmetric Nearest Neighbor

#### 4.7.1. Overview

This filter blurs the image preserving edges. It is very effective in noise reduction maintaining sharp edges.

It works comparing each pixel to its neighboring pixels and to 1 or 2 pairs of symmetric pixels around the center.

4 symmetric pairs

#### 4.7.2. Activating the filter

You can find this filter through Filters → Enhance → Symmetric Nearest Neighbor….

#### 4.7.3. Options

图 17.35. “Symmetric Nearest neighbor” filter options

Presets, Preview, Split view

  These options are common to GEGL-based filters. Please refer to 第 2 节 “Common Features”.

Radius

  Radius, in pixels, of square pixel region. Width and height of this region are radius*2+1:

Pairs

  You can select 1 or 2 pairs : higher number preserves more acute features.

#### 4.7.4. Example

Left: original..............Right: filter applied

4.6. Red Eye Removal |  | 4.8. Sharpen (Unsharp Mask)

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