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 which is defined as
 
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> 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.
 
* 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.
 
* Under the Parameters tab, select a single band or a multiband file as input layer.

Revision as of 15:59, 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 \(G_{2D}(x,y,\sigma)=\frac{1}{\sqrt{2 \pi \sigma^2}}e^{-\frac{x^2+y^2}{2\sigma^2}}\) 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
Personal tools
Namespaces

Variants
Actions
Navigation
Development
Toolbox
Print/export