<?php
function linearStretchImage($imagePath, $blackThreshold, $whiteThreshold) {
$imagick = new \Imagick(realpath($imagePath));
$pixels = $imagick->getImageWidth() * $imagick->getImageHeight();
$imagick->linearStretchImage($blackThreshold * $pixels, $whiteThreshold * $pixels);
header("Content-Type: image/jpg");
echo $imagick->getImageBlob();
}
?>