Removing red eye in PHP using Imagick - php

Question

I'm trying to adapt the script available here [http://www.fmwconcepts.com/imagemagick/redeye/index.php][1] in PHP using the API version of Imagick.
Actually, the selection is done in jQuery then passed to the following script to draw the selection.
Here's my code so far:
<?php
extract($_POST);
// Load the original image
$image = new Imagick($path);
// Duplicate and desaturate the original image
$image2 = clone $image;
$image2->modulateImage(15, 0, 100);
// Create the mask on which the selection will be drawn
$image3 = clone $image;
$image3->colorfloodfillimage(new ImagickPixel('white'), 18, new ImagickPixel('white'), 0, 1);
foreach ($redeye as $selection){
try{
$draw = new ImagickDraw();
$draw->setstrokewidth(0);
$draw->setstrokecolor(new ImagickPixel('black'));
$draw->setFillColor(new ImagickPixel( 'black' ));
$draw->setfillalpha(1);
$draw->ellipse( $selection['ox'], $selection['oy'], $selection['rx'], $selection['ry'], 0, 360 );
$image3->drawImage($draw);
} catch (ImagickException $ie){
echo $ie->getMessage();
}
}
?>
I know very little about image processing and don't know how to merge the 3 layers.
I don't really understand the code of the convert function when merging the layer.
Any help would be greatly appreciated!
EDIT:
convert $tmpA1 $tmpA2 $tmpA3 -compose over -composite $tmpA2
As I understand this should be written like the following using the API:
$image2->compositeImage($image3,Imagick::COMPOSITE_OVER, 0, 0);
$image2->compositeImage($image2,Imagick::COMPOSITE_OVER, 0, 0);
$image2->compositeImage($image,Imagick::COMPOSITE_OVER, 0, 0);
Then
convert $tmpA2 \( $tmpA1 -modulate 100,0,100 \) $tmpA4 -compose over -composite $outfile
Should be written like that:
$image->modulateImage(100, 0, 100);
$image->compositeImage($image,Imagick::COMPOSITE_OVER,0, 0);
$image->compositeImage($image2,Imagick::COMPOSITE_OVER,0, 0);
But I don't understand this part:
convert $tmpA3 ( +clone -morphology close disk:$rad $dilation ) -compose difference -composite -auto-level -negate -threshold 0 -negate $tmpA4