how to decode del.icio.us's captcha

This is a uncompleted script, maybe you can help me to finish it.

I try to decode the del.icio.us's captcha with the next php script.
<br /><?php<br />/* @author tiekil@gmail.com */<br />class Code {<br /> protected $_srcFile;<br /> public function __construct($file) {<br /> $this->_srcFile = $file;<br /> }<br /><br /> public function filter() {<br /> $size = getimagesize($this->_srcFile);<br /> $im = imagecreatefrompng($this->_srcFile);<br /> imagejpeg($im, $this->_srcFile . '.jpg', 100); //convert the png to jpeg<br /> $im = imagecreatefromjpeg($this->_srcFile . '.jpg');<br /> for($x=0;$x<$size[0];$x++) {<br /> for($y=0;$y<$size[1];$y++) {<br /> $rgb = imagecolorat($im,$x,$y);<br /> $r = ($rgb >> 16) & 0xFF;<br /> if ($r > 100) { // set the light color to white<br /> $rgb = imagecolorallocate($im, 255, 255, 255);<br /> } else { //javascript:void(0)<br />Publish Post set the dark color to black<br /> $rgb = imagecolorallocate($im, 0, 0, 0);<br /> }<br /> imagesetpixel($im, $x, $y, $rgb);<br /><br /> # remove the "Z" block<br /> // x-1, y-1 black<br /> $rgb = imagecolorat($im,$x-1,$y-1);<br /> $r1 = ($rgb >> 16) & 0xFF;<br /> // x-1, y white<br /> $rgb = @imagecolorat($im,$x-1,$y);<br /> $r2 = ($rgb >> 16) & 0xFF;<br /> // x, y-1 white<br /> $rgb = @imagecolorat($im,$x,$y-1);<br /> $r3 = ($rgb >> 16) & 0xFF;<br /> if (($r3 == 255) && ($r2 == 255) && ($r1 == 0)) {<br /> $rgb = imagecolorallocate($im, 255, 255, 255);<br /> if ($rgb) {<br /> imagesetpixel($im, $x-1, $y-1, $rgb);<br /> }<br /> }<br /> }<br /> }<br /> # remove others<br /> for($x=0;$x<$size[0];$x++) {<br /> for($y=0;$y<$size[1];$y++) {<br /> $rgb = imagecolorat($im,$x,$y);<br /> $r = ($rgb >> 16) & 0xFF;<br /> $rgb = imagecolorat($im,$x-1,$y);<br /> $r2 = ($rgb >> 16) & 0xFF;<br /> $rgb = imagecolorat($im,$x+1,$y);<br /> $r3 = ($rgb >> 16) & 0xFF;<br /> $rgb = imagecolorat($im,$x,$y-1);<br /> $r4 = ($rgb >> 16) & 0xFF;<br /> $rgb = imagecolorat($im,$x,$y+1);<br /> $r5 = ($rgb >> 16) & 0xFF;<br /> # clean dot<br /> if (($r == 0) && ($r2 == 255) && ($r3 == 255) && ($r4 == 255) <br /> && ($r5 == 255)) {<br /> $rgb = imagecolorallocate($im, 255,255,255);<br /> imagesetpixel($im, $x, $y, $rgb);<br /> }<br /> # clean bottom border<br /> if (($y == $size[1]-1) && ($r == 0) && ($r2 == 255) && ($r3 == 255)<br /> && ($r4 == 255)) {<br /> $rgb = imagecolorallocate($im, 255,255,255);<br /> imagesetpixel($im, $x, $y, $rgb);<br /> }<br /> # clean right border<br /> if (($x == $size[0]-1) && ($r == 0) && ($r2 == 255) && ($r4 == 255) <br /> && ($r5 == 255)) {<br /> $rgb = imagecolorallocate($im, 255,255,255);<br /> imagesetpixel($im, $x, $y, $rgb);<br /> }<br /> }<br /> }<br /> imagejpeg($im, $this->_srcFile . '.new.jpg',100);<br /> }<br />}<br /><br /># demo<br />$code = new Code('1986312480.png');<br />$code->filter();<br />?><br />
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