Advanced Search

Как определить сходство двух изображений

/ Published in: PHP
Save to your folder(s)
Класс для сравнения двух изображений. Возвращает расстояние Хэмминга. Подробнее можно почитать здесь: http://habrahabr.ru/blogs/image_processing/120562/

Expand | Embed | Plain Text

Copy this code and paste it in your HTML 
  1. class Hamming
  2. {
  3. 	private function _resizeImage($from_file, $to_file, $width, $height, $quality)
  4. 	{
  5. 		$img1 = imagecreatefromjpeg($from_file);
  6. 		$img2 = imagecreatetruecolor($width, $height);
  7.  
  8. 		imagecopyresampled($img2, $img1, 0, 0, 0, 0, $width, $height, imagesx($img1), imagesy($img1));
  9.  
  10. 		imagejpeg($img2, $to_file, $quality);
  11.  
  12. 		imagedestroy($img1);
  13. 		imagedestroy($img2);
  14. 	}
  15.  
  16. 	private function _grayScaleImage($filename)
  17. 	{
  18. 		$img_size 	= getimagesize($filename);
  19. 		$width 		= $img_size[0];
  20. 		$height		= $img_size[1];
  21. 		$img 		= imagecreate($width,$height);
  22.  
  23. 		for ($c = 0; $c < 256; $c++)
  24. 		{
  25. 			imagecolorallocate($img, $c, $c, $c);
  26. 		}
  27.  
  28. 		$img2 = imagecreatefromjpeg($filename);
  29. 		imagecopymerge($img,$img2,0,0,0,0, $width, $height, 100);
  30. 		imagejpeg($img, $filename);
  31. 		imagedestroy($img);
  32. 	}
  33.  
  34. 	private function _getPixelValue($filename, $x, $y)
  35. 	{
  36. 		$image 	= imagecreatefromjpeg($filename);
  37. 		$color 	= imagecolorat($image, $x, $y);
  38. 		$r 		= ($color >> 16) & 0xFF;
  39. 		$g 		= ($color >> 8) & 0xFF;
  40. 		$b 		= $color & 0xFF;
  41.  
  42. 		imagedestroy($image);
  43.  
  44. 		return array('r'=>$r, 'g'=>$g, 'b'=>$b);
  45. 	}
  46.  
  47. 	private function _getChainOfBits($image)
  48. 	{
  49. 		$tmpfile = sys_get_temp_dir() . uniqid(md5(rand()), true) . '.jpg';
  50. 		$this->_resizeImage($image,  $tmpfile, 8, 8, 100);
  51. 		$this->_grayScaleImage($tmpfile);
  52.  
  53. 		$a = array();
  54. 		for($i=0; $i<8; $i++)
  55. 		{
  56. 			for($j=0; $j<8; $j++)
  57. 			{
  58. 				$rgb = $this->_getPixelValue($tmpfile, $i, $j);
  59. 				$a[] = $rgb['r'];
  60. 			}
  61. 		}
  62. 		$avrg = (int)(array_sum($a) / count($a));
  63.  
  64. 		$s = '';
  65. 		foreach ($a as $value)
  66. 		{
  67. 			$s .= ($value > $avrg ? '0' : '1');
  68. 		}
  69. 		unlink($tmpfile);
  70.  
  71. 		return $s;
  72. 	}
  73.  
  74. 	public function getDistance($image1, $image2)
  75. 	{
  76. 		$bits1 = $this->_getChainOfBits($image1);
  77. 		$bits2 = $this->_getChainOfBits($image2);
  78.  
  79. 		$distance = 0;
  80. 		for($i=0; $i<64; $i++)
  81. 		{
  82. 			$bit1 = $bits1[$i];
  83. 			$bit2 = $bits2[$i];
  84.  
  85. 			if ( $bit1 != $bit2 )
  86. 			{
  87. 				$distance++;
  88. 			}
  89. 		}
  90.  
  91. 		return $distance;
  92. 	}
  93. }
  94.  
  95.  
  96. $hamming = new Hamming();
  97. $distance = $hamming->getDistance('image-1.jpg', 'image-2.jpg');
  98.  
  99. echo $distance;

URL: http://habrahabr.ru/blogs/image_processing/120562/

Report this snippet


Comments

RSS Icon Subscribe to comments

You need to login to post a comment.