detect_face.py

import cv2
import face_recognition

# Get a reference to webcam
video_capture = cv2.VideoCapture("/dev/video1")

face_locations = []

while True:
    # Grab a single frame of video
    ret, frame = video_capture.read()

    # Convert the image from BGR color (which OpenCV uses) to RGB color (which face_recognition uses)
    rgb_frame = frame[:, :, ::-1] # reverse order

    # Find all the faces in the current frame of video
    face_locations = face_recognition.face_locations(rgb_frame)
    # Display the results
    for top, right, bottom, left in face_locations:
        # Draw a box around the face
        cv2.rectangle(frame, (left, top), (right, bottom), (0, 255, 0), 2)# green rectangle around where face is

    # Display the resulting image
    cv2.imshow('Video', frame)

    # Hit 'q' on the keyboard to quit!
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

print(f'Number of faces detected : {len(face_locations)}')
# Release handle to the webcam
video_capture.release()
cv2.destroyAllWindows()