import cv2
import numpy as np

def main():
    capture = cv2.VideoCapture(2)
    cv2.namedWindow("Camera", cv2.WINDOW_AUTOSIZE)

    while True:
        ret, frame = capture.read()

        frame_mono = np.mean(frame, axis=2)
        intensity = np.mean(frame_mono)

        print(f"\033[H\033[2J{intensity:6.3f}")

        cv2.imshow('Camera', frame)

        if cv2.waitKey(1) == ord('q'):
            break


if __name__ == "__main__":
    main()