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.

 

   

Settings
 
Name Default Description
Radius 1.5 pixels

Determines the scale of fine detail that will be removed. Low values remove only very fine detail while high values remove larger levels of detail.

This value represents the standard deviation of the Gaussian function.

 

   

Workings
 

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.

 

   

Example
 

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