Applying Mixture Model
The mixture model is a component that implements a raster decomposition using the mixture model strategy. The spatial resolution of remote sensing satellites, in general, allows that a single pixel contains more than a target (for example vegetation + shadow + soil). The mixture model algorithms allow decomposing the raster into fraction images, where the value of the resultant pixels indicates the fraction of each target inside the pixel.
The main information needed to execute a mixture model are:
One Raster file.
A map of pure endmembers, which are pixel values where the user knows the exact proportion of a component.
Sensor information for each band, if available.
The available methods in TerraAmazon are:
Linear: It is calculated by the following equation:
ri is the pixel value at band i,
aij is the known value of the component j at band i,
xj is the proportion of component j,
ei is the estimation error for band i.
PCA: The component matrix is transformed using Principal Component Analysis, and the fraction of each component is obtained by using the proper number of eigenvectors.
Select PROCESSING → RASTER PROCESSING → MIXTURE MODEL in the main menu.
Selection of the layer with the desired raster (Layer Search)
On the List of Layers select the raster layer to apply the Mixture Model.
Optionally use Filter By Name field giving part of the layer name to help find the layer in the list.
Press the Next button to go to next step or the Cancel button to close the dialog.
Mixture Model parameters
Type - Select the Type of mixture model to be used and set specific parameters (the parameters will vary depending on the selected contrast type).
Options
Create error images: indicate that output raster will include the error bands.
Raster Bands Tab: Select the input Bands and the Sensor information for each band.
Components Tab: it lists the Names and the Values (one for each band) of the components acquired over the image (for example samples of soil, water and shadow). The number of components (samples) and bands must be the same.
Use tool
to enable the acquisition of components (samples) through the
interface Raster Navigator. This interface offers several tools (such
as zoom, color composition) to help on collecting good samples.
Use tool
to import a .json file.
Use tool
to export a .json file.
Use tool
to remove undesired samples from the list.
Spectral curves: click on Selected to see only selected curve or click on All to see all curves on the chart..
To customize chart click on the Graphic Style button.
Press the Next button to go to next step.
Output information
Raster Info - First
press
and inform the folder where the resulting file will be saved.
Name - inform the raster name.
Extra Parameters - if there are some.
Press the Finish button to save the resulting raster.