(PECL imagick 2.0.0)
Imagick::edgeImage — Enhance edges within the image
$radius
   )Enhance edges within the image with a convolution filter of the given radius. Use radius 0 and it will be auto-selected.
radiusThe radius of the operation.
   Returns TRUE on success.
  
Throws ImagickException on error.
Example #1 Imagick::edgeImage()
<?php
function edgeImage($imagePath, $radius) {
    $imagick = new \Imagick(realpath($imagePath));
    $imagick->edgeImage($radius);
    header("Content-Type: image/jpg");
    echo $imagick->getImageBlob();
}
?>