OpenCV

mask.py

import cv2, matplotlib
import numpy as np
import matplotlib.pyplot as plt

bgr_img = cv2.imread('images/landscape.jpg')
img = cv2.cvtColor(bgr_img, cv2.COLOR_BGR2HSV)
blue_min = np.array([100, 0, 0], np.uint8)
blue_max = np.array([140, 255, 255], np.uint8)
wh_min = np.array([0, 0, 180], np.uint8)
wh_max = np.array([180, 60, 255], np.uint8)
blue = cv2.inRange(img, blue_min, blue_max)
white = cv2.inRange(img, wh_min, wh_max)
inv_mask = cv2.bitwise_or(white, blue)
mask = cv2.bitwise_not(inv_mask)
plt.imshow(mask, cmap=plt.get_cmap('gray'))
mask_rgb = cv2.cvtColor(mask, cv2.COLOR_GRAY2RGB)
masked_rgb = cv2.bitwise_and(cv2.cvtColor(bgr_img, cv2.COLOR_BGR2RGB), mask_rgb)
plt.imshow(masked_rgb)

apt-get install python-opencv python-matplotlib 
ipython notebook --pylab=inline