Filtering is a process in which each pixel value in a raster map is replaced with a new value. The new value is obtained by applying a certain function to each input pixel and the neighborhood.
Linear filters use a linear combination of all pixels in a rectangle around the input pixel. They can have a user-defined size; further, you may wish to insert your own values in the matrix and determine your own gain value.
To create a user-defined linear filters:
The Create Filter dialog box appears in which you can define the size of the filter. Subsequently, you can enter the values of the cells in the filter in the Filter editor.
Tip:
The Average filter, Majority filters, Median filters, the Pattern filter, Rank Order filters, and the Standard Deviation filter may have a user-defined size, rank or threshold. These filters can be modified Filter : dialog box; they can also be defined on the command line.
See also: