User Defined Filter

The User Defined Filter resampling option determines the gray level from the weighted average of all the pixels in a square or rectangular kernel surrounding the input coordinates and assigns the value to the output coordinates.

The weight applied to each pixel in the kernel is defined in a Kernel File that you create with a text editor such as Notepad. Click Browse to select the Kernel File.

For example, if you wanted to create a 3-by-3 Kernel File, you could define it as this:

 3   3 
-1  -1   0
 1   3   1
 1  -1  -1

The Kernel File moves over the image. Each pixel that falls within the kernel is multiplied by the corresponding number in the filter, and then summed to produce the output value.