php 以图搜图

感知哈希算法

count <=5 匹配最相似

count > 10 两张不同的图片

var_dump(ImageHash::run('./1.png', './psb.jpg'));

<?php

class ImageHash {

const FILE_NOT_FOUND = '-1';

const FILE_EXTNAME_ILLEGAL = '-2';

private function __construct() {}

public static function run($src1, $src2) {

static $self;

if(!$self) $self = new static;

if(!is_file($src1) || !is_file($src2)) exit(self::FILE_NOT_FOUND);

$hash1 = $self->getHashValue($src1);

$hash2 = $self->getHashValue($src2);

if(strlen($hash1) !== strlen($hash2)) return false;

$count = 0;

$len = strlen($hash1);

for($i = 0; $i < $len; $i++) if($hash1[$i] !== $hash2[$i]) $count++;

return $count <= 10 ? true : false;

}

public function getImage($file) {

$extname = pathinfo($file, PATHINFO_EXTENSION);

if(!in_array($extname, ['jpg','jpeg','png','gif'])) exit(self::FILE_EXTNAME_ILLEGAL);

$img = call_user_func('imagecreatefrom'. ( $extname == 'jpg' ? 'jpeg' : $extname ) , $file);

return $img;

}

public function getHashValue($file) {

$w = 8;

$h = 8;

$img = imagecreatetruecolor($w, $h);

list($src_w, $src_h) = getimagesize($file);

$src = $this->getImage($file);

imagecopyresampled($img, $src, 0, 0, 0, 0, $w, $h, $src_w, $src_h);

imagedestroy($src);

$total = 0;

$array = array();

for( $y = 0; $y < $h; $y++) {

for ($x = 0; $x < $w; $x++) {

$gray = (imagecolorat($img, $x, $y) >> 8) & 0xFF;

if(!isset($array[$y])) $array[$y] = array();

$array[$y][$x] = $gray;

$total += $gray;

}

}

imagedestroy($img);

$average = intval($total / ($w * $h * 2));

$hash = '';

for($y = 0; $y < $h; $y++) {

for($x = 0; $x < $w; $x++) {

$hash .= ($array[$y][$x] >= $average) ? '1' : '0';

}

}

var_dump($hash);

return $hash;

}

}