OpenCV magical code – Hidden Bottle

import cv2
import numpy as np

cap = cv2.VideoCapture(0)

while (1):

    # Take each frame
    _, frame = cap.read()

    # Convert BGR to HSV
    hsv = cv2.cvtColor(frame, cv2.COLOR_BGR2HSV)

    # define range of blue color in HSV
    lower_blue = np.array([90, 50, 70])
    upper_blue = np.array([128, 255, 255])

    # Threshold the HSV image to get only blue colors
    mask = cv2.inRange(hsv, lower_blue, upper_blue)

    # Bitwise-AND mask and original image
    res = cv2.bitwise_and(frame, frame, mask=mask)

    cv2.imshow('frame', frame)

    cv2.imshow('res', res)
    k = cv2.waitKey(5) & 0xFF
    if k == 27:
        break

cv2.destroyAllWindows()