Simple OpenCV object tracking demo

object_tracking.py

import cv2

cap = cv2.VideoCapture(0)

tracker = cv2.TrackerMOSSE_create()

roi = None

while True:
    _, frame = cap.read()

    if roi is not None:
        success, box = tracker.update(frame)
        if success:
            x, y, w, h = [int(v) for v in box]
            cv2.rectangle(frame, (x, y), (x + w, y + h), (0, 255, 0), 2)

    cv2.imshow('webcam', frame)

    key = cv2.waitKey(25) & 0xFF
    if key == ord('s'):
        roi = cv2.selectROI('webcam', frame, fromCenter=False, showCrosshair=True)
        tracker.init(frame, roi)
    elif key == ord('q'):
        break

cap.release()
cv2.destroyAllWindows()