messigray.py

# -*- coding: utf-8 -*-
 """
 Created on Wed Jan 1 20:49:33 2014@author: duan
 """
 import numpy as np
 import cv2img = cv2.imread('messi5.jpg',0)
 cv2.imshow('image',img)
 k = cv2.waitKey(0)
 if k == 27: # wait for ESC key to exit
     cv2.destroyAllWindows()
 elif k == ord('s'): # wait for 's' key to save and exit
     cv2.imwrite('messigray.png',img)
     cv2.destroyAllWindows()

警告：如果你用的是64 位系统，你需要将 k = cv2.waitKey(0) 这行改成
k = cv2.waitKey(0)&0xFF。