Chris Light
Veteran
ok, ok...the term itself was misleading, but based on your explanation, it makes total sense...thanks so much for taking the time!One of the things to process an image to increase 'edge' information at least for how humans perceive things, is to 'blur' then add/subtract (depending on what you want to do...) that blurred image from a multiple of the original image...
It is a form of contrast enhancement that takes the local neighbors of a pixel into account, rather than a global contrast enhancement.
The 'mask' has to do with how many neighboring pixels are used in the filter process, as well as the shape. In digital processing the 'shape' is often a square region around a pixel. in more theoretical works, often a circle is used...
The 'unsharp' means using the blurred pixels in the neighborhood for the calculations. One could use values for the mask that has an arbitrary set of numbers...