To detect the object movement in circular motion

detectCircularGesture.py

	# loop over the set of tracked points
	for i in range(1, len(pts)):
		# if either of the tracked points are None, ignore them
		if pts[i - 1] is None or pts[i] is None:
			continue

		# otherwise, compute the thickness of the line and draw the connecting lines
		thickness = int(np.sqrt(args["buffer"] / float(i + 1)) * 2.5)
		cv2.line(frame, pts[i - 1], pts[i], (0, 0, 255), thickness)

	isCirclePts = [p for p in pts if p is not None]

	if (len(isCirclePts) > 30):

		vectors = [np.subtract(t, s) for s, t in 
			   		    zip(isCirclePts, isCirclePts[1:])]

		vectors = [vector for vector in vectors 
			   			if np.linalg.norm(vector) > 5]

                # To find concavity, check vector direction using Right Hand rule
		determ = [np.linalg.det([s, t]) 
			                  for s, t in zip (vectors, vectors[1:])]

		directionChange = [determ[i] * determ[i + 1] 
				                for i in range (len(determ) - 1)]

		# when the movement of the object is 
		# insignificant, consider it stationary
		if len(directionChange) < 10:
			alarmTriggered = False
			continue