First of all, What Face Detection/Recognition is?

Is a computer technology that determines the locations and sizes of human faces in arbitrary (digital) images. It detects facial features and ignores anything else, such as buildings, trees and bodies.

How to do this in PHP?

OpenCV wrapper to detect faces with PHP. The extension offers the two new functions: face_count() and face_detect(). In princible, they differ only by their return value. The first returns only the number of faces found on the given image and the other an associative array of their coordinates. face_count() serves only to save the loops for counting. Examples:

Face detection in pure PHP (without OpenCV). This is a PHP Class to face recognition without OpenCV, it use an data file, but not external libraries. We can use it with few code:

 
$detector = new Face_Detector('detection.dat');
$detector->face_detect('maurice_svay_150.jpg');
$detector->toJpeg();
 

Example:

Enjoy it!

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function getRepetitions($value, array $values){
	$length = count($values);
	if($length==0)
		return FALSE;
	$repetitions = 0;
	foreach($values as $v){
		if($v==$value)
			$repetitions++;
	}
	return $repetitions;
}
print getRepetitions(3,array(3,3,3,5,6,4,3,6,5,4,6,3,2,8,8))."\n";
 

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Here's the function. Enjoy it!

 
function getMode(array $valores){
	$longitud = count($valores);
	$repeticiones = array();
	if($longitud==0)
		return FALSE;
	foreach($valores as $valor){
		$repeticiones[$valor]=0;
		for($i=0;$i<$longitud;$i++){
			if($valores[$i]==$valor)
				$repeticiones[$valor]++;
		}
	}
	unset($valores,$longitud,$i,$valor);
	asort($repeticiones);
	$llaves = array_keys($repeticiones);
	return array_pop($llaves);
}
print getMode(array(3,3,3,5,6,4,3,6,5,4,6,3,2,8,8))."\n";
 

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function tweetme_bitly_link($id) {
 
	if (function_exists('revcanonical_shorten') &&
                                $link = revcanonical_shorten($id)) {
		return $link;
	} else {
		$link = get_permalink($id);
               /**Williams Mendez **/
	$ob = @simplexml_load_file('http://api.microuri.com/get.php?url='.$link);
	if(is_object($ob) && isset($ob->Response) && strlen($ob->Response))
	return $ob->Response;
		return file_get_contents('http://bit.ly/api?url=' . $link);
	}
}
 

Note: This url shortening and wordpress hack is provided by Williams Mendez.

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function valid_ip($ip) {
    return preg_match("/^([1-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])" .
            "(\.([0-9]|[1-9][0-9]|1[0-9][0-9]|2[0-4][0-9]|25[0-5])){3}$/", $ip);
}
 

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The problem of longest common subsequence arises whenever we search for similarities across multiple texts. A particularly important application is in finding a consensus among DNA sequences. The genes for building particular proteins evolve with time, but the functional regions must remain consistent in order to work correctly. By finding the longest common subsequence of the same gene in different species, we learn what has been conserved over time.

The longest common substring problem is a special case of edit distance, when substitutions are forbidden and only exact character match, insert, and delete are allowable edit operations. Under these conditions, the edit distance between p and t is n+m-2 |lcs(p,t)|, since we can delete the missing characters from p to the lcs(p,t) and insert the missing characters from $t$ to transform p to t. This is particularly interesting because the longest common subsequence can be faster to compute than edit distance.

For More Information about it, just google it!.

The Implementation.

/**
 * Implementación de el Algoritmo "Longer Common SubString" en dos (2) Cadenas dadas.
 *
 * @param string $a
 * @param string $b
 * @return integer
 */
function lcs($a, $b) {
	if (! is_string ( $a ) || ! is_string ( $b ))
		return false;
	$m = strlen ( $a );
	$n = strlen ( $b );
	for($i = 0; $i < $m; $i ++)
		$c [$i] [0] = 0;
	for($j = 0; $j < $n; $j ++)
		$c [0] [$j] = 0;
	for($i = 1; $i <= $m; $i ++) {
		for($j = 1; $j <= $n; $j ++) {
			if ($a [$i] == $b [$j])
				$c [$i] [$j] = $c [$i] [$j - 1] + 1;
			else {
				if ($c [$i - 1] [$j] >= $c [$i] [$j - 1])
					$c [$i] [$j] = $c [$i - 1] [$j];
				else
					$c [$i] [$j] = $c [$i] [$j - 1];
			}
		}
	}
	return $c [$m] [$n];
}

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In Unix and other computer multitasking operating systems, a daemon is a computer program that runs in the background, rather than under the direct control of a user; they are usually initiated as background processes. Typically daemons have names that end with the letter "d": for example, syslogd, the daemon that handles the system log, or sshd, which handles incoming SSH connections.

In the Microsoft DOS environment, such programs were written as Terminate and Stay Resident (TSR) software. On Microsoft Windows systems, programs called services perform the functions of daemons. They run as processes, usually do not interact with the monitor, keyboard, and mouse, and may be launched by the operating system at boot time. With Windows NT and later versions, one can configure and manually start and stop Windows services using the Control Panel -> Services applet.

Daemons in PHP

There is a PHP class created by Kevin van Zonneveld that is very helpfull, you can download from here. I think everyone have to take a look. For more information go here: Create Daemons in PHP.

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Then on Internet I found this: PHP.js, an open source project in which they try to port PHP functions to JavaScript. By including the PHP.JS library in your own projects, you can use your favorite PHP functions on the client-side. This convenience may speed up development for PHP developers who are increasingly confronted with client-side technology.

The History of PHP.JS

A developer called Kevin van Zonneveld was once working on a project with a lot of client(JS) / server(PHP) interaction, and he found himself coding PHP functions (like base64_decode & urldecode) in JavaScript to smoothen communication between the two languages. He stored the stored the functions in a file called php.js which was included in the project. Kevin decided to share the little library online, which triggered the enthusiasm of a lot of PHP developers longing for PHP functionality in JavaScript. The project was open sourced in 2008, and many people contributed their own functions in the comments sections of Kevin's blog. It was decided that the library deserved a bigger home, and a face of its own, and so the PHP.JS core team developed the phpjs.org website.

List of functions

To see the list of functions click here PHP.JS: Functions Overview.

More Information:  http://phpjs.org/

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PHP have predefined variables like $_POST, $_GET, $_SESSION and more. One of this variables is $_SERVER that is an array containing information such as headers, paths, and script locations. The entries in this array are created by the web server.

The index that we going to use is: "HTTP_ACCEPT_LANGUAGE" because this index shows the contents of the Accept-Language: header from the current request, if there is one. Example: 'es-ar,es;q=0.8,en-us;q=0.5,en;q=0.3'

The Code
Now we can create the code.

As we can see, the first 2 letters says the main language and the next two specifies the country. Another options that we have is to take the "q" values, those values shows the percentage probabilityfor others language including the main one.

In just 1 line we could determine the visitor language:

<?php echo substr ( $_SERVER ["HTTP_ACCEPT_LANGUAGE"], 0, 2 ); ?>
 

And that's it!!

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The get_browser() function

The get_browser() function tells what the user's browser is capable of. This function was is supported by PHP 4 and PHP 5. To use this function we need to do 2 things: First, we need to configure the browscap directive on the php.ini file. Second, we need to have a browscap.ini file, that is the file that contain all the up-to-date information about web browsers. The get_browser() function just parse this file,match the user-agent and return an object or an array with the specific configuration of the browser.

To get the browscap file, just go there: Downloads :: Browser Capabilities Project.

When you got the file, open your php.ini and find the browscap line, write the path for the file and restart the web server.

Example:

 
<?php
echo $_SERVER['HTTP_USER_AGENT'] . "\n\n";
$browser = get_browser(null, true);
print_r($browser);
?>
 

Then there is an element called ismobiledevice that contain an empty value if is not a mobile device or 1, if the device is mobile.

 
<?php
$browser = get_browser(null, true);
echo $browser['ismobiledevice'];
?>
 

Alternative (and better) option

If you are using a shared hosting, maybe you can't edit the php.ini and the ini_set() function doesn't work either. So this is an alternative option.

Click here to download the function: detect_mobile_browser

Using the functions

 
<?php
include 'detect_mobile_browser.php';
$browser_info = php_get_browser('php_browscap.ini',$_SERVER['HTTP_USER_AGENT']);
if(ismobiledevice($browser_info))
echo "<strong>Mobile device detected</strong>.Your browser is: <strong>{$browser_info['parent']}</strong>.";
else
echo "No mobile device detected.";
?>
 

Note: You can view an example here: http://demo.dwstudioinc.net/mobileupload/detectar.php. I did some test using a Sony Ericsson K550 and G1 (using Android) and works perfect!.

And that's it!

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