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

img = cv2.imread('flower.jpg' ,cv2.IMREAD_GRAYSCALE)

##cv2.imshow('image' , img)
##cv2.waitKey(0)
##cv2.destroyAllWindows()
plt.imshow(img, cmap='gray' , interpolation='bicubic')
plt.plot([50,100],[80,100],'c',linewidth=5)
plt.show()
cv2.imwrite('flowergray.png' ,img)
