Reconocimiento facial con php

01 <?php
02 // 
03 // This program is free software; you can redistribute it and/or
04 // modify it under the terms of the GNU General Public License
05 // as published by the Free Software Foundation; either version 2
06 // of the License, or (at your option) any later version.
07 // 
08 // This program is distributed in the hope that it will be useful,
09 // but WITHOUT ANY WARRANTY; without even the implied warranty of
10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 // GNU General Public License for more details.
12 // 
13 // You should have received a copy of the GNU General Public License
14 // along with this program; if not, write to the Free Software
15 // Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. 
16 // 
17 // @Author Karthik Tharavaad 
18 // karthik_tharavaad@yahoo.com
19 // @Contributor Maurice Svay
20 // maurice@svay.Com
21  
22 class Face_Detector {
23  
24   protected $detection_data;
25   protected $canvas;
26   protected $face;
27   private $reduced_canvas;
28  
29  #El constructor de clase carga el archivo .dat y lo asigna a una variable
30   public function __construct($detection_file = 'detection.dat') {
31     if (is_file($detection_file)) {
32       $this->detection_data = unserialize(file_get_contents($detection_file));
33     } else {
34       throw new Exception("No se pudo cargar el archivo");
35     }
36   }
37  
38  #Dado un archivo imagen 
39   public function face_detect($file) {
40     if (!is_file($file)) {
41       throw new Exception("No se puede carga el archivo $file");
42     }
43   #crea una nueva imagen temporal
44     $this->canvas = imagecreatefromjpeg($file);
45     $im_width = imagesx($this->canvas);
46     $im_height = imagesy($this->canvas);
47  
48     //Resample before detection?
49     $ratio = 0;
50     $diff_width = 320 - $im_width;
51     $diff_height = 240 - $im_height;
52     if ($diff_width > $diff_height) {
53       $ratio = $im_width / 320;
54     } else {
55       $ratio = $im_height / 240;
56     }
57  
58     if ($ratio != 0) {
59       $this->reduced_canvas = imagecreatetruecolor($im_width / $ratio, $im_height / $ratio);
60       imagecopyresampled($this->reduced_canvas, $this->canvas, 0, 0, 0, 0, $im_width / $ratio, $im_height / $ratio, $im_width, $im_height);
61  
62       $stats = $this->get_img_stats($this->reduced_canvas);
63       $this->face = $this->do_detect_greedy_big_to_small($stats['ii'], $stats['ii2'], $stats['width'], $stats['height']);
64       $this->face['x'] *= $ratio;
65       $this->face['y'] *= $ratio;
66       $this->face['w'] *= $ratio;
67     } else {
68       $stats = $this->get_img_stats($this->canvas);
69       $this->face = $this->do_detect_greedy_big_to_small($stats['ii'], $stats['ii2'], $stats['width'], $stats['height']);
70     }
71     return ($this->face['w'] > 0);
72   }
73  
74  
75   public function toJpeg() {
76     $color = imagecolorallocate($this->canvas, 255, 0, 0); //red
77     imagerectangle($this->canvas, $this->face['x'], $this->face['y'], $this->face['x']+$this->face['w'], $this->face['y']+ $this->face['w'], $color);
78     header('Content-type: image/jpeg');
79     imagejpeg($this->canvas);
80   }
81  #esto solo para JSON
82   public function toJson() {
83     return "{'x':" . $this->face['x'] . ", 'y':" . $this->face['y'] . ", 'w':" . $this->face['w'] . "}";
84   }
85  
86   public function getFace() {
87     return $this->face;
88   }
89  
90   protected function get_img_stats($canvas){
91     $image_width = imagesx($canvas);
92     $image_height = imagesy($canvas);   
93     $iis = $this->compute_ii($canvas, $image_width, $image_height);
94     return array(
95       'width' => $image_width,
96       'height' => $image_height,
97       'ii' => $iis['ii'],
98       'ii2' => $iis['ii2']
99     );     
100   }
101  
102   protected function compute_ii($canvas, $image_width, $image_height ){
103     $ii_w = $image_width+1;
104     $ii_h = $image_height+1;
105     $ii = array();
106     $ii2 = array();   
107  
108     for($i=0; $i<$ii_w; $i++ ){
109       $ii[$i] = 0;
110       $ii2[$i] = 0;
111     }            
112  
113     for($i=1; $i<$ii_w; $i++ ){ 
114       $ii[$i*$ii_w] = 0;    
115       $ii2[$i*$ii_w] = 0; 
116       $rowsum = 0;
117       $rowsum2 = 0;
118       for($j=1; $j<$ii_h; $j++ ){
119         $rgb = ImageColorAt($canvas, $j, $i);
120         $red = ($rgb >> 16) & 0xFF;
121         $green = ($rgb >> 8) & 0xFF;
122         $blue = $rgb & 0xFF;
123         $grey = ( 0.2989*$red + 0.587*$green + 0.114*$blue )>>0; // this is what matlab uses
124         $rowsum += $grey;
125         $rowsum2 += $grey*$grey;
126  
127         $ii_above = ($i-1)*$ii_w + $j;
128         $ii_this = $i*$ii_w + $j;
129  
130         $ii[$ii_this] = $ii[$ii_above] + $rowsum;
131         $ii2[$ii_this] = $ii2[$ii_above] + $rowsum2;
132       }
133     }
134     return array('ii'=>$ii, 'ii2' => $ii2);
135   }
136  
137   protected function do_detect_greedy_big_to_small( $ii, $ii2, $width, $height ){
138     $s_w = $width/20.0;
139     $s_h = $height/20.0;
140     $start_scale = $s_h < $s_w ? $s_h : $s_w;
141     $scale_update = 1 / 1.2;
142     for($scale = $start_scale; $scale > 1; $scale *= $scale_update ){
143       $w = (20*$scale) >> 0;
144       $endx = $width - $w - 1;
145       $endy = $height - $w - 1;
146       $step = max( $scale, 2 ) >> 0;
147       $inv_area = 1 / ($w*$w);
148       for($y = 0; $y < $endy ; $y += $step ){
149         for($x = 0; $x < $endx ; $x += $step ){
150           $passed = $this->detect_on_sub_image( $x, $y, $scale, $ii, $ii2, $w, $width+1, $inv_area);
151           if( $passed ) {
152             return array('x'=>$x, 'y'=>$y, 'w'=>$w);
153           }
154         } // end x
155       } // end y
156     } // end scale
157     return null;
158   }
159  
160   protected function detect_on_sub_image( $x, $y, $scale, $ii, $ii2, $w, $iiw, $inv_area){
161     $mean = ( $ii[($y+$w)*$iiw + $x + $w] + $ii[$y*$iiw+$x] - $ii[($y+$w)*$iiw+$x] - $ii[$y*$iiw+$x+$w] )*$inv_area;
162     $vnorm = ( $ii2[($y+$w)*$iiw + $x + $w] + $ii2[$y*$iiw+$x] - $ii2[($y+$w)*$iiw+$x] - $ii2[$y*$iiw+$x+$w] )*$inv_area - ($mean*$mean);  
163     $vnorm = $vnorm > 1 ? sqrt($vnorm) : 1;
164  
165     $passed = true;
166     for($i_stage = 0; $i_stage < count($this->detection_data); $i_stage++ ){
167       $stage = $this->detection_data[$i_stage]; 
168       $trees = $stage[0]; 
169  
170       $stage_thresh = $stage[1];
171       $stage_sum = 0;
172  
173       for($i_tree = 0; $i_tree < count($trees); $i_tree++ ){
174         $tree = $trees[$i_tree];
175         $current_node = $tree[0];  
176         $tree_sum = 0;
177         while( $current_node != null ){
178           $vals = $current_node[0];
179           $node_thresh = $vals[0];
180           $leftval = $vals[1];
181           $rightval = $vals[2];
182           $leftidx = $vals[3];
183           $rightidx = $vals[4];
184           $rects = $current_node[1];
185  
186           $rect_sum = 0;
187           for( $i_rect = 0; $i_rect < count($rects); $i_rect++ ){
188             $s = $scale;
189             $rect = $rects[$i_rect];
190             $rx = ($rect[0]*$s+$x)>>0;
191             $ry = ($rect[1]*$s+$y)>>0;
192             $rw = ($rect[2]*$s)>>0; 
193             $rh = ($rect[3]*$s)>>0;
194             $wt = $rect[4];
195  
196             $r_sum = ( $ii[($ry+$rh)*$iiw + $rx + $rw] + $ii[$ry*$iiw+$rx] - $ii[($ry+$rh)*$iiw+$rx] - $ii[$ry*$iiw+$rx+$rw] )*$wt;
197             $rect_sum += $r_sum;
198           } 
199  
200           $rect_sum *= $inv_area;
201  
202           $current_node = null;
203           if( $rect_sum >= $node_thresh*$vnorm ){
204             if( $rightidx == -1 ) 
205               $tree_sum = $rightval;
206             else
207               $current_node = $tree[$rightidx];
208           } else {
209             if( $leftidx == -1 )
210               $tree_sum = $leftval;
211             else
212               $current_node = $tree[$leftidx];
213           }
214         } 
215         $stage_sum += $tree_sum;
216       } 
217       if( $stage_sum < $stage_thresh ){
218         return false;
219       }
220     } 
221     return true;
222   }
223 }

01 <?php
02  require ('Face_Detector.php'); 
03     $detector = new Face_Detector('detection.dat');  
04     $detector->face_detect('FOTO.jpg');  
05     $detector->toJpeg();  
06 ?>