(PECL imagick 2.0.0)
Imagick::reduceNoiseImage — Smooths the contours of an image
Smooths the contours of an image while still preserving edge information. The algorithm works by replacing each pixel with its neighbor closest in value. A neighbor is defined by radius. Use a radius of 0 and Imagick::reduceNoiseImage() selects a suitable radius for you.
TRUE on success.
Throws ImagickException on error.