motion_detector.py

import cv2
import numpy as np

# pass 0 to read video from default webcam if available, 1 for external webcam
cap = cv2.VideoCapture("airplanes.mp4")

ret1, frame1 = cap.read()
ret2, frame2 = cap.read()

while True:
    frame1_gray = cv2.cvtColor(frame1, cv2.COLOR_BGR2GRAY)
    frame2_gray = cv2.cvtColor(frame2, cv2.COLOR_BGR2GRAY)
    frame1_blur = cv2.GaussianBlur(frame1_gray, (21, 21), 0)
    frame2_blur = cv2.GaussianBlur(frame2_gray, (21, 21), 0)

    diff = cv2.absdiff(frame1_blur, frame2_blur)

    thresh = cv2.threshold(diff, 20, 255, cv2.THRESH_BINARY)[1]
    final = cv2.dilate(thresh, None, iterations=2)

    masked = cv2.bitwise_and(frame1, frame1, mask=thresh)

    # count the number of white pixels in thresholded image
    white_pixels = np.sum(thresh) / 255

    rows, cols = thresh.shape
    total = rows * cols

    # if the number of white pixels are more than 1% of the total image
    # trigger an action
    if white_pixels > 0.01 * total:
        font = cv2.FONT_HERSHEY_SIMPLEX
        cv2.putText(frame1, 'Movement Detected', (10, 50), font, 1,
                    (0, 0, 255), 2, cv2.LINE_AA)

    cv2.imshow("Motion", frame1)

    frame1 = frame2
    ret, frame2 = cap.read()

    if not ret:
        break

    key = cv2.waitKey(10)
    if key == ord('q'):
        break


cv2.destroyAllWindows()