nr Noise Reduction Blur Bound
Sets the threshold at which noise is removed. Valid values are in the range
100. If no value is supplied,
nr will be set to the default value of
20. If only
nr is set, then
nrs will be set to its default.
nr value sets the threshold at which noise is removed. Pixels that fall below this threshold will be blurred. Pixels above the threshold will be sharpened according to the
nrs parameter value. If neither value is supplied, then no noise reduction will be applied.