(PECL imagick 2.0.0)
Imagick::medianFilterImage — Applies a digital filter
$radius
   )Applies a digital filter that improves the quality of a noisy image. Each pixel is replaced by the median in a set of neighboring pixels as defined by radius.
radiusThe radius of the pixel neighborhood.
   Returns TRUE on success.
  
Throws ImagickException on error.
Example #1 Imagick::medianFilterImage()
<?php
function medianFilterImage($radius, $imagePath) {
    $imagick = new \Imagick(realpath($imagePath));
    @$imagick->medianFilterImage($radius);
    header("Content-Type: image/jpg");
    echo $imagick->getImageBlob();
}
?>