Re: how to call that strange filter? sharpening or unsharpening?

walala wrote:

> I remember there is a type of image filter, which actually sharpens the
> image, but people call it "unsharpening" filter...
> 
> Am I correct?
> 
> what's the formal name of that kind of 3x3 filter?
> 
> Sharpening Unsharpening Mask?
> 

It's an spatial highpass filter with unsharp mask. By definition this is a
highpass filter where the filtered image data is added back to the original
data (since using only the highpass image is not very useful for many
applications). The amount of original image information in the resulting
image is given by the unsharp mask.

-- 
Dipl.-Inform. Hendrik Belitz
Central Laboratory of Electronics
Research Center Juelich