Gaussian filter

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The Gaussian smoothing filter is used for noise reduction and removing details. The filter is similar to the arithmetic mean filter but it uses a different kernel that represents the shape of a 2 dimensional Gaussian distribution which is defined as \(G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}}\) where \sigma determines the width of the kernel.

  • In the search engine of the Processing Toolbox, type Smoothing and select Smoothing (gaussian) under Image Filtering of the Orfeo Toolbox.
  • Under the Parameters tab, select a single band or a multiband file as input layer.
  • Select gaussian from the drop-down list as Smoothing Type.
  • Adjust the Radius of a circular element in pixel size.

Qgis smooth gauss.png

Figure A: Input image: pansharpend Sentinel-2 composite (RGB=B7,B6,B5), University Göttingen Campus North
Figure B: Output image: Gaussian filtered Sentinel-2 composite (RGB=B7,B6,B5), University Göttingen Campus North
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