import cv2
import matplotlib.pyplot as plt
from matplotlib.pyplot import imread as imread

plt.figure(1)
img_DR = cv2.imread('img.tif',0)
edges_DR = cv2.Canny(img_DR,20,40)

plt.subplot(121),plt.imshow(img_DR)
plt.title('Original Image'), plt.xticks([]), plt.yticks([])
plt.subplot(122),plt.imshow(edges_DR,cmap = 'gray')
plt.title('Edge Image'), plt.xticks([]), plt.yticks([])

plt.show()