opencv

import numpy as np
import cv2 as cv

img = cv.imread('test.jpg',0)     # 以灰度模式读取图像，0为灰度模式，1为彩色模式

cv.imshow('image',img)            # 显示图像，“image”和“img”分别为窗口和图片的名称，
cv.waitKey(0)
cv.destroyAllWindows()            # 删除窗口

cv.destroyWindow("image")

import numpy as np
import cv2 as cv

img = cv.imread('test.jpg',0)

cv.imwrite('test01.png',img)      # 以名为test01格式为png保存图像

import numpy as np
import cv2 as cv
from matplotlib import pyplot as plt

img = cv.imread('test.jpg',0)
plt.imshow(img, cmap = 'gray', interpolation = 'bicubic')
plt.xticks([]), plt.yticks([])  # 隐藏X与Y轴
plt.show()