The following python code shows the conversion process of the detected face to blur using the OpenCV module. The method is used to convert blur is GaussianBlur(Source, ksize, sigmaX) . source: The image. ksize  : (kernel.width, kernel.height). kernel width and kernel height can differ but they must be positive and odd. Program :  import cv2 trainedDataset = cv2.CascadeClassifier( "haarcascade_frontalface_default.xml" ) img = cv2.imread( "images/Elon Musk.jpg" ) faces = trainedDataset.detectMultiScale(img) for x , y , w , h in faces:     cv2.rectangle(img , (x , y , w , h) , ( 50 , 50 , 50 ) , 2 )     img[y:y + h , x:x + w] = cv2.GaussianBlur(img[y:y + h , x:x + w] , ( 93 , 93 ) , 0 )     cv2.imshow( "Image" , img)     cv2.waitKey( 0 ) Output :  If you have any doubts in the code please refer face detection in image file using python .