Image JPG compare

compareimage.php

<?php

function compareImages($imagePathA, $imagePathB, $accuracy)
{

    // load base image

    $bim = imagecreatefromjpeg($imagePathA);

    // create comparison points

    $bimX = imagesx($bim);
    $bimY = imagesy($bim);
    $pointsX = $accuracy * 5;
    $pointsY = $accuracy * 5;
    $sizeX = round($bimX / $pointsX);
    $sizeY = round($bimY / $pointsY);

    // load image into an object

    $im = imagecreatefromjpeg($imagePathB);

    // loop through each point and compare the color of that point

    $y = 0;
    $matchcount = 0;
    $num = 0;
    for ($i = 0; $i <= $pointsY; $i++) {
        $x = 0;
        for ($n = 0; $n <= $pointsX; $n++) {
            $rgba = imagecolorat($bim, $x, $y);
            $colorsa = imagecolorsforindex($bim, $rgba);
            $rgbb = imagecolorat($im, $x, $y);
            $colorsb = imagecolorsforindex($im, $rgbb);
            if (colorComp($colorsa['red'], $colorsb['red']) && colorComp($colorsa['green'], $colorsb['green']) && colorComp($colorsa['blue'], $colorsb['blue'])) {

                // point matches

                $matchcount++;
            }

            $x+= $sizeX;
            $num++;
        }

        $y+= $sizeY;
    }

    // take a rating of the similarity between the points, if over 90 percent they match.

    $rating = $matchcount * (100 / $num);
    return $rating;
}

function colorComp($color, $c)
{

    // test to see if the point matches - within boundaries

    if ($color >= $c - 2 && $color <= $c + 2) {
        return true;
    }
    else {
        return false;
    }
}


$imagePathA = 'https://www.w3.org/MarkUp/Test/xhtml-print/20050519/tests/jpeg420exif.jpg';
$imagePathB = 'https://www.w3.org/MarkUp/Test/xhtml-print/20050519/tests/jpeg420exif.jpg';

print_r(compareImages($imagePathA, $imagePathB, 100));