ptyhon_opencv 图像的基本操作

1、cv2.imread()  to read an image

     cv2.IMREAD_COLOR:  load a color image

     cv2.IMREAD_GRAYSCALE: loads image in grayscale mode

     cv2.IMREAD_UNCHANGED: Loads image as such including alpha channel

　　

下面是读一幅图像和显示一幅图像，cv.waitKey() is a keyboard function. Its argument is the time in milliseconds, 里面的参数也可能是一个具体的字母。 cv.destroyAllWindows() simply destroys all the windows.

cv.destroyWindow() where you pass the exact window name as the argument.

 

#encoding=utf-8
import cv2 as cv
import numpy as np

#Load an color image in grayscale
img=cv.imread('C:\Users\Administrator\Desktop\lena.jpg',0)

#imshow an image
cv.imshow('img',img)
cv.waitKey(0)#这里要注意字母大小写的问题
cv.destoryAllWindows()

2、下面是定义一个窗口的名字，并在窗口中显示图像，其中cv.WINDOW_AUTOSIZE()默认显示图像的大小，cv.WINDOW_NORMAL()可以根据图像的大小自动调节窗口的大小。

import cv2 as cv
import numpy as np

img=cv.imread('C:\Users\Administrator\Desktop\lena.jpg',0)

cv.namedWindow('image',cv.WINDOW_NORMAL)
cv.imshow('image',img)
cv.waitKey(0)
cv.destroyAllWindows()

3、Use the function cv.imwrite()   to save an image.  First argument is the file name,secong argument is the image you want to save.s

cv.imwrite('C:\Users\Administrator\Desktop\lena.jpg',img)