Contrast

• Decorrelation Enhancement:  Uses the principal components to contrast the raster.

• Histogram Equalization:  Using this method, the histogram of the image will be equalized automatically.

• Linear: The user defines a new minimum and maximum values for the pixels in the image. The algorithm then applies a linear function over the pixels using this 2 values.

• Mean and Standard Deviation: The contrasted image will have a predefined mean and standard deviation, defined by the user.

• Log: The contrasted image will be created by using a log function.

• Square: The contrasted image will be created by using a square function.

• Square Root: he contrasted image will be created by using a square root function.

    Wizard Page 1 - Selection of the layer to apply the contrast (Layer Search)

1. On the List of Layers select the raster layer to apply the contrast. 
2. Optionally use Filter By Name field giving part of the layer name to help find the layer in the list.
3. Press Next  to go to next step or Cancel to close the dialog. 

1. Select the Type of contrast to be used (Linear,  Histogram or Mean and Standard deviation).
2. In Raster Bands check the desired bands and set the specific parameters which will varies depending on the contrast type chosen.  Double Click over the cell of each parameter to make the cell editable and then change the value and press enter:
1. If  Linear, Square, Square Root or Log: set the new value for Minimum and/or Maximum,
2. If Histogram Equalization: set the new value for  Maximum,
3. If Mean and Standard Deviation: set the new value for Mean and/or Std Dev.
4. If Decorrelation Enhancement: none extra parameters will be necessary.
   
3. On the Preview  tab click on to have a preview of the contrast with the parameters informed.
4. The Histogram tab presents the histogram to help in the contrast operation.
• The Input histogram represents the histogram of the selected band.
• The Output is as the histogram would be if the contrast was applied.
• Using the mouse buttons you can purchase the pixel value from the histogram, helping to define the parameters of each type of contrast.
5. Press Next to apply the contrast or Back to go to the previous wizard page.

    Wizard Page 3 - Output information

1. Raster Info - First press and inform the folder where the resulting file will be saved.
2. Name - inform the raster name.
3. Extra Parameters - if there are some, see the details on how to inform then here.
4. Press Finish to save the resulting contrasted raster or Back to go to the previous wizard page.