annotation.md

A basic juggling tracker in Python

All CV2 juggling trackers follow the same basic pattern:

Setup

Video Capture

cap = cv2.VideoCapture(FILENAME)

Set up object detector

object_detector = cv2.createBackgroundSubtractorMOG2(
                    history=DETECTOR_HISTORY,
                    varThreshold=DETECTOR_THRESHOLD)

Set globals used in read loop

# Get first frame
ret, frame = cap.read()
tracked_objects = []

Video read loop

track() and display_in_frame() are user defined

while ret:

    mask = object_detector.apply(frame)

    contours, _ = cv2.findContours( mask,
                                    cv2.RETR_TREE,
                                    cv2.CHAIN_APPROX_SIMPLE )

    tracked_objects=track(tracked_objects, contours)

    frame=display_in_frame(frame, tracked_objects)

    # Create a named window
    cv2.namedWindow("Juggling", cv2.WINDOW_NORMAL)
    cv2.imshow("Juggling", frame)

    key = cv2.waitKey(frame_delay)
    if key == 27:
        break

    ret, frame = cap.read()

Free Resources after read loop

cap.release()
cv2.destroyAllWindows()