unsharp[=l|cWxH:amount[:l|cWxH:amount]]
unsharp mask / gaussian blur
l
Apply effect on luma component.
c
Apply effect on chroma components.
<width>x<height>
width and height of the matrix, odd sized in both direc-
tions (min = 3x3, max = 13x11 or 11x13, usually some-
thing between 3x3 and 7x7)
amount
Relative amount of sharpness/blur to add to the image (a
sane range should be -1.5-1.5).
<0: blur
>0: sharpen