face_detection.py

import cv2

facedetector = cv2.CascadeClassifier('./cascades/haarcascade_frontalface_default.xml')
cap = cv2.VideoCapture(0)
cap.set(3, 640)
cap.set(4, 480)

while(True):
    ret, frame = cap.read()
    frame = cv2.flip(frame,+1)
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    faces = facedetector.detectMultiScale(
        gray,
        scaleFactor=1.2,
        minNeighbors=5,
        minSize=(20, 20)
    )
    for (x,y,w,h) in faces:
        cv2.rectangle(frame, (x,y), (x+w, y+h), (0,0,255), 2)
        roi_gray = gray[y:y+h, x:x+h]
        roi_color = frame[y:y+h, x:x+w]
    cv2.imshow('video', frame)
    k = cv2.waitKey(30)
    if k == 27:
        break

cap.release()
cv2.destroyAllWindows()