### 7.6. RGB ノイズ...

#### 7.6.1. 概観

図17.163 「RGB ノイズ」フィルターの適用例

元画像

Filter applied

The RGB Noise filter adds a normally distributed noise to a layer or a selection. It uses the RGB color model to produce the noise (noise is added to red, green and blue values of each pixel). A normal distribution means, that only slight noise is added to the most pixels in the affected area, while less pixels are affected by more extreme values. (If you apply this filter to an image filled with a solid gray color and then look at its histogram, you will see a classic bell-shaped Gaussian curve.)

ノイズがとても自然に見える仕上がりになります。

#### 7.6.2. Activating the Filter

This filter is found in the main menu under Filters → Noise → RGB Noise….

#### 7.6.3. オプション

図17.164 「RGBノイズ」フィルターのオプション

Presets, 「Input Type」, Clipping, Blending Options, プレビュー, Merge filter, Split view

  | 注記
  These options are described in 「Common Features」.

相関ノイズ

  Noise may be additive (uncorrelated) or multiplicative (correlated - also known as speckle noise). When checked, every channel value is multiplied by a normal distributed value. So the noise depends on the channel values: a greater channel value leads to more noise, while dark colors (small values) tend to remain dark.

RGB 独立

  When this radio button is checked, you can move each RGB slider separately. Otherwise, the sliders R, G and B will be replaced by a single slider Value. The same relative noise will then be added to all channels in each pixel, so the hue of pixels does not change much.

Linear RGB

  Operate on linearized RGB color data.

Gaussian distribution

  Use a gaussian noise distribution. When unchecked, a linear noise distribution is used instead.

赤, 緑, 青, 透明度

  These slidebars and adjacent input boxes allow to set noise level (0.00-1.00) in each channel.

  これらのスライダーは具体的にはノイズをつけるときの正規分布における標準偏差の値を設定しています。 使用される標準偏差は設定された値の半分です。 (値の範囲 1.00 がチャンネルでとりうる最高値から最低値までの幅に相当します。)

乱数種, New Seed

  This option controls the randomness of the filter. The Random seed box lets you manually enter a seed for the randomization algorithm used. You can also generate a random seed by pressing the New Seed button. If the same random seed is used in the same situation, the filter produces exactly the same results. A different random seed produces different results.

7.5. つまむ... |  | 7.7. ごまかす...

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