Gaussian Blur Effect

A Gaussian Blur is a general purpose blur filter. This removes fine image detail and noise leaving only larger scale changes. Gaussian Blurs produce a very pure smoothing effect without side effects.

A Gaussian Blur is distinct from other blurs in that it has a well defined effect on different levels of detail within an image. As the level of detail becomes smaller the filter lets through less and less. With other types of blur (e.g. Mean Filter) the amount let through may vary considerably.

As well as having this well defined and consistent frequency response, certain characteristics of the Gaussian function mean that large blurs can be applied much faster than other similar kinds of filters.

The following example images show the effect of Gaussian Blur.

[C#]
void function() {
  using (Doc doc = new Doc()) {
    AddImagePage(doc, img3); // original image
    doc.Rendering.Save("EffectGaussianBlur.jpg");
    using (ImageLayer layer = AddImagePage(doc, img3)) {
      using (EffectOperation effect = new EffectOperation("Gaussian Blur")) {
        effect.Parameters["Radius"].Value = 1.2;
        effect.Apply(layer.PixMap);
      }
    }
    doc.Rendering.Save("EffectGaussianBlur12.jpg");
    using (ImageLayer layer = AddImagePage(doc, img3)) {
      using (EffectOperation effect = new EffectOperation("Gaussian Blur")) {
        effect.Parameters["Radius"].Value = 2.5;
        effect.Apply(layer.PixMap);
      }
    }
    doc.Rendering.Save("EffectGaussianBlur25.jpg");
    using (ImageLayer layer = AddImagePage(doc, img3)) {
      using (EffectOperation effect = new EffectOperation("Gaussian Blur")) {
        effect.Parameters["Radius"].Value = 5.0;
        effect.Apply(layer.PixMap);
      }
    }
    doc.Rendering.Save("EffectGaussianBlur50.jpg");
  }
}

[Visual Basic]
Sub ...
  Using doc As New Doc()
    AddImagePage(doc, img3)
    ' original image
    doc.Rendering.Save("EffectGaussianBlur.jpg")
    Using layer As ImageLayer = AddImagePage(doc, img3)
      Using effect As New EffectOperation("Gaussian Blur")
        effect.Parameters("Radius").Value = 1.2
        effect.Apply(layer.PixMap)
      End Using
    End Using
    doc.Rendering.Save("EffectGaussianBlur12.jpg")
    Using layer As ImageLayer = AddImagePage(doc, img3)
      Using effect As New EffectOperation("Gaussian Blur")
        effect.Parameters("Radius").Value = 2.5
        effect.Apply(layer.PixMap)
      End Using
    End Using
    doc.Rendering.Save("EffectGaussianBlur25.jpg")
    Using layer As ImageLayer = AddImagePage(doc, img3)
      Using effect As New EffectOperation("Gaussian Blur")
        effect.Parameters("Radius").Value = 5.0
        effect.Apply(layer.PixMap)
      End Using
    End Using
    doc.Rendering.Save("EffectGaussianBlur50.jpg")
  End Using
End Sub

Original Image before Gaussian Blur

After Gaussian Blur Radius 1.2 pixels

After Gaussian Blur Radius 2.5 pixels

After Gaussian Blur Radius 5.0 pixels