Gaussian filter

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.

Gaussian filter using OTB

Does currently not work in OTB plugin for QGIS 3.4. Use OTB standalone.

• 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.

Gaussian filter using SAGA

• In the search engine of the Processing Toolbox, type Gaussian and select Gaussian filter under Raster Filter of SAGA.
• Under the Parameters tab, select a single band file as Grid.
• Select Circle from the drop-down list as Search Mode.
• Choose 1 as Standard deviation
• Use the 3 pixels as Radius.

Figure A: Input image: 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