Created
November 7, 2010 19:56
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This is a very basic optical character recognition script written in PHP. This is untested and serves merely a proof of concept. As noted in the comments, adjusting the sample size can improve results, since with a large sample size on a small image there
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<?php | |
/* create a test image */ | |
$im = @imagecreate(100, 20) or die("Cannot Initialize new GD image stream"); | |
$background_color = imagecolorallocate($im, 255, 255, 255); | |
$text_color = imagecolorallocate($im, 0, 0, 0); | |
imagestring($im, 1, 5, 5, "Hello, World!", $text_color); | |
/*** | |
* Assumptions: | |
* A monochrome image where characters are black | |
* A single character is connected | |
* Characters are disjointed by white space | |
*/ | |
$width = imagesx($im); | |
$height = imagesy($im); | |
/*** | |
* Notes: | |
* The smaller the sample size the more accurate it will be, | |
* however, it will take longer. Larger images can use a larger | |
* sample size wihtout compromizing much accuracy. | |
*/ | |
$x_sample = 1; | |
$y_sample = 1; | |
$last = 0; | |
for($i = 0; $i < $width; $i++) { | |
$col = array(); | |
for($j = 0; $j < $height; $j++) { | |
$col[$j] = imagecolorat($im, $i, $j); | |
} | |
if(($current = array_sum($col)) > 0) { | |
if($last == 0) { | |
$l = 0; | |
} | |
for($k = 0; $k < $height; $k++) { | |
if(($l % $x_sample) == 0) { | |
if(($k % $y_sample) == 0) { | |
$sample .= $col[$k]; | |
} | |
} | |
} | |
$l++; | |
$last = $current; | |
} else { | |
$last = 0; | |
} | |
if(!empty($sample) && $last == 0) { | |
echo $sample . "\n"; | |
$sample = ""; | |
} | |
} | |
?> |
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