PHP实现搜索相似图片_PHP教程

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;

									  }

									}

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

方法二：

									hash($f);

									 }

									 return $isString ? $result[0] : $result;

									 }

									 public function checkIsSimilarImg($imgHash, $otherImgHash){

									 if (file_exists($imgHash) && file_exists($otherImgHash)){

									  $imgHash = $this->run($imgHash);

									  $otherImgHash = $this->run($otherImgHash);

									 }

									 if (strlen($imgHash) !== strlen($otherImgHash)) return false;

									 $count = 0;

									 $len = strlen($imgHash);

									 for($i=0;$i<$len;$i++){

									  if ($imgHash{$i} !== $otherImgHash{$i}){

									  $count++;

									  }

									 }

									 return $count <= (5 * $rate * $rate) ? true : false;

									 }

									 public function hash($file){

									 if (!file_exists($file)){

									  return false;

									 }

									 $height = 8 * $this->rate;

									 $width = 8 * $this->rate;

									 $img = imagecreatetruecolor($width, $height);

									 list($w, $h) = getimagesize($file);

									 $source = $this->createImg($file);

									 imagecopyresampled($img, $source, 0, 0, 0, 0, $width, $height, $w, $h);

									 $value = $this->getHashValue($img);

									 imagedestroy($img);

									 return $value;

									 }

									 public function getHashValue($img){

									 $width = imagesx($img);

									 $height = imagesy($img);

									 $total = 0;

									 $array = array();

									 for ($y=0;$y<$height;$y++){

									  for ($x=0;$x<$width;$x++){

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

									  if (!is_array($array[$y])){

									   $array[$y] = array();

									  }

									  $array[$y][$x] = $gray;

									  $total += $gray;

									  }

									 }

									 $average = intval($total / (64 * $this->rate * $this->rate));

									 $result = '';

									 for ($y=0;$y<$height;$y++){

									  for ($x=0;$x<$width;$x++){

									  if ($array[$y][$x] >= $average){

									   $result .= '1';

									  }else{

									   $result .= '0';

									  }

									  }

									 }

									 return $result;

									 }

									 public function createImg($file){

									 $ext = $this->getFileExt($file);

									 if ($ext === 'jpeg') $ext = 'jpg';

									 $img = null;

									 switch ($ext){

									  case 'png' : $img = imagecreatefrompng($file);break;

									  case 'jpg' : $img = imagecreatefromjpeg($file);break;

									  case 'gif' : $img = imagecreatefromgif($file);

									 }

									 return $img;

									 }

									 public function getFileExt($file){

									 $infos = explode('.', $file);

									 $ext = strtolower($infos[count($infos) - 1]);

									 return $ext;

									 }

									}

调用方式如下：

									require_once "Imghash.class.php";

									$instance = ImgHash::getInstance();

									$result = $instance->checkIsSimilarImg('chenyin/IMG_3214.png', 'chenyin/IMG_3212.JPG');