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

"Hendrik Belitz" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> 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

Hi, Hendrik,

Thanks for your answer!

How do you name this filter then ?

ff=[ -0.040053   0.121750   -0.040053;
        0.121750    0.679317    0.121750;
       -0.040053   0.121750   -0.040053];

Is it a low pass + unsharpening mask?

Thanks a lot

-Walala