Gaussian filter

From AWF-Wiki
(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
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.
+
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 <math>G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}}</math>
 
<math>G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}</math>
 
<math>G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}</math>
 
* In the search engine of the Processing Toolbox, type '''Smoothing''' and select '''Smoothing (gaussian)''' under Image Filtering of the Orfeo Toolbox.
 
* In the search engine of the Processing Toolbox, type '''Smoothing''' and select '''Smoothing (gaussian)''' under Image Filtering of the Orfeo Toolbox.

Revision as of 15:55, 20 November 2017

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 \(G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}}\) \(G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}\)

  • 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
Personal tools
Namespaces

Variants
Actions
Navigation
Development
Toolbox
Print/export