def fpsCal(frame2, prevTime):
    curTime = time.time()
    sec = curTime - prevTime
    prevTime = curTime
    fps = 1/(sec)
    str = "FPS : %0.1f" % fps
    cv2.putText(frame2, str, (10, 50), cv2.FONT_HERSHEY_SIMPLEX, 0.6, (0, 255, 0))
    return prevTime