use CV\Face\LBPHFaceRecognizer;
//use ...;

$src = imread('facePic.jpg');
$gray = cvtColor($src, COLOR_BGR2GRAY);
equalizeHist($gray, $gray);
$faceRecognizer = LBPHFaceRecognizer::create();
/* ... */ //get $images and $labels for train
$faceRecognizer->train($images, $labels);//How to get $image and $labels, see the document
/* ... */ //Face detection using CascadeClassifier
$faceLabel = $faceRecognizer->predict($gray);
/* ... */ //draw face and name

//Obama.php
use function CV\{ imread, imshow, waitkey, namedWindow};

$im = imread('Obama.png');//load image
namedWindow('This is Obama id card',WINDOW_FULLSCREEN);//create window
imshow('This is Obama id card',$im);//show image on window

waitkey(0);

$gray = imread('Obama.png',IMREAD_GRAYSCALE);
//or
use  function CV\{ cvtColor};
$gray = cvtColor($im, COLOR_BGR2GRAY);

use CV\{Mat,Scalar, Point, Size};
use function CV\{ellipse, imwrite, waitKey};
use const CV\{CV_8UC3};

$windowWidth = 600;
$thickness = 2;
$lineType = 8;
$matScalar = new Scalar(0,0,0);
$mat = new Mat($windowWidth, $windowWidth, CV_8UC3, $matScalar);
$point=new Point($windowWidth/2, $windowWidth/2);
$size=new Size($windowWidth/4, $windowWidth/16);
$scalar=new Scalar(255, 129, 0);
for($i = 0; $i <= 360; $i += 45){
    ellipse($mat,$point,$size,$i,0,360,$scalar,$thickness,$lineType);
}
imwrite('./tests/ellipse.png',$mat);