<?php
	# ------- The graph values in the form of associative array
	function de00T($l1,$a1,$b1,$l2,$a2,$b2) {

    $C1 = sqrt(pow($a1,2) + pow($b1,2));
    $C2 =  sqrt(pow($a2,2) + pow($b2,2));
	

    $meancO = ($C1 + $C2) / 2;
    $logmeanc =log10($meancO);
	
    $log25 = log10(25);
	$cratio = sqrt(pow(10,($logmeanc*7 - log10((pow(10,($logmeanc*7)) + pow(10,($log25*7)))))));
	
    $g = 0.5 * (1 - $cratio);
	
	$a1 = (1 + $g) * $a1;
    $a2 = (1 + $g) * $a2;
	
	
    $C1 = sqrt(pow($a1,2) + pow($b1,2));
    $C2 =  sqrt(pow($a2,2) + pow($b2,2));
	
		//';calculate hue angles
    If ($b1 == 0) {
        If ($a1 >= 0) {
            $h1 = 0;}
        Else {
            $h1 = 180;}}
	Else {
        $h1 = rad2deg(atan2($b1, $a1));
    } 
       
	
    If ($b2 == 0) {
        If ($a2 >= 0) {
            $h2 = 0;}
        Else {
            $h2 = 180; }
        }
    Else {
        $h2 = rad2deg(atan2($b2, $a2));
    }
	
    If ($h1 < 0) {
        $h1 = $h1 + 360;}
       
    If ($h2 < 0) {
        $h2 = $h2 + 360;}
		
	/////////////////////////////////	
	if (abs($h1-$h2)<180) {
		$dhm = $h2-$h1;
	}
	else{
		$dhm=360-abs($h1-$h2);
	}
	    $meanh = $h1 + $h2;
		
    If ($dhm > 180) {
        $dhm = $dhm - 360;
        $meanh = $meanh - 360;
    }
    
    If ($dhm < -180) {
        $dhm = $dhm + 360;
        $meanh = $meanh - 360;
    }
	$meanh = $meanh / 2;
	
	
	$T=1-0.17*cos(deg2rad($meanh-30))+0.24*cos(deg2rad(2*$meanh))+0.32*cos(deg2rad(3*$meanh+6))-0.2*cos(deg2rad(4*$meanh-63));
	
	$SH=1+0.015*(($C2+$C1)/2)*$T;

	
	$dH=2*pow(($C2*$C1),0.5)*sin(deg2rad($dhm/2));
	
	$SC=1+0.045*($C1+ $C2)/2;
	$dC=$C2 - $C1;
	$SL=1+(0.015*pow((($l2+$l1)/2-50),2))/pow((20+pow((($l2+$l1)/2-50),2)),0.5);
	$dL=$l1 - $l2;
	$KL=1;$KC=1;$KH=1;
	$meanc=($C1+$C2)/2;
	$theta=30*EXP(-(pow((($meanh-275)/25),2)));
	$RC=2*pow(pow($meanc,7)/(pow($meanc,7)+pow(25,7)),0.5);

	$RT=-sin(2*deg2rad($theta))*$RC;
	$deltaE2000x=pow((pow(($dL/($SL*$KL)),2)+pow(($dC/($SC*$KC)),2)+pow(($dH/($SH*$KH)),2)+$RT*($dC/($SC*$KC))*($dH/($SH*$KH))),0.5);
//echo "de00:".$meanc."<br>";
	return $deltaE2000x;	

}
?>