在php中比较2个图像

$image1 = imagecreatefromjpeg('image1.jpg');
$image2 = imagecreatefromjpeg('image2.jpg');

$width = imagesx($image1);
$height = imagesy($image1);

$difference = 0;

for ($x = 0; $x < $width; $x++) {
    for ($y = 0; $y < $height; $y++) {
        $rgb1 = imagecolorat($image1, $x, $y);
        $rgb2 = imagecolorat($image2, $x, $y);

        $r1 = ($rgb1 >> 16) & 0xFF;
        $g1 = ($rgb1 >> 8) & 0xFF;
        $b1 = $rgb1 & 0xFF;

        $r2 = ($rgb2 >> 16) & 0xFF;
        $g2 = ($rgb2 >> 8) & 0xFF;
        $b2 = $rgb2 & 0xFF;

        $difference += abs($r1 - $r2) + abs($g1 - $g2) + abs($b1 - $b2);
    }
}

$difference = $difference / ($width * $height);

if ($difference < 5) {
    echo "两个图像相似";
} else {
    echo "两个图像不相似";
}

imagedestroy($image1);
imagedestroy($image2);

$image1 = new Imagick('image1.jpg');
$image2 = new Imagick('image2.jpg');

$result = $image1->compareImages($image2, Imagick::METRIC_MEANSQUAREERROR);

if ($result[1] < 0.05) {
    echo "两个图像相似";
} else {
    echo "两个图像不相似";
}

$image1->destroy();
$image2->destroy();