Erosion of low-contrast regions

Erosion of low-contrast regions is carried out for a complete elimination of hitting the low-contrast regions into high-contrast regions. One iteration of erosion deletes extreme pixels of raster regions of low-contrast classes.

In erosion parametres it is necessary to specify which classes are the low-contrast. For each class it is necessary to enter the number of iterations and the minimum size of regions. The minimum size is necessary in order that completely not to erase raster area at doing erosion.

Results of classification before performing the erosion:

Results of the erosion application to the results of classification:

This results of erosion are obtained with the following values of parametres

On a classification raster you can see that the hydrography not everywhere is correctly classified, and the main channel of the river has a large area.    Therefore the number of iterations is chosen so to delete all small regions at saving the main channel. Small regions of the rivers are deleted completely because the minimum size of area is not limited (is equal 0).

Fields extremely seldom fall on the wood, there are small regions where the size of overlapping may be up to 7 pixels, therefore the number of iterations is 7. Raster regions in width less than 14 pixels at erosion may be deleted. In order not to lose them the minimum size of 1000 pixels is entered.