L32_face_detection_video.py

import cv2

# classifiers già pronti in ./opencv/data/haarcascades

face_cascade = cv2.CascadeClassifier('./opencv/data/haarcascades/haarcascade_frontalface_default.xml')

cap = cv2.VideoCapture(0) # da webcam
while cap.isOpened():
    _, img = cap.read()
    img_gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
    faces = face_cascade.detectMultiScale(
        img_gray, scaleFactor=1.1, minNeighbors=4)

    for (x, y, w, h) in faces:
        cv2.rectangle(img, (x, y), (x+w, y+h), (0, 255, 0), 3)

    cv2.imshow('Video', img)
    if cv2.waitKey(1) & 0xFF == 27:
        break

cap.release()
cv2.destroyAllWindows()