Contrast


The Contrast operation is used to enhance the visual quality of the image represented by a raster file.

The available methods in TerraLib are:


Select a layer, draw it, then select this option in the main menu
PROCESSING → RASTER PROCESSING → CONTRAST:

  1. Layer: it will be filled with the layer NAME visible in the map display. Nothing else can be done until you select an area to apply the contrast.
  2. Histogram Area:  choose an area to apply the contrast 
  3. The Histogram shows the histogram of the first band initially (default), or the histogram of the band selected in Raster Bands.

  4. Raster Bands:  select each band and observe the Histogram(graphic). Now set the specific parameters which varies depending on the contrast type chosen in 6. Double click over the cell of each parameter to make the cell editable and then change the value and press enter:

  5. Data Type Range:  it will be used to set the minimum and maximum values of data type range in output image.
  6. Type:  Select one of the available contrast type.
  7. Output:  Click on the    to inform the Directory and output Layer name.
  8. Press the OK button to save the resulting contrasted raster image.
Hint: The contrasted  image will be added as a new layer at the TerraView project.