python版opencv入门（1）

读入图片

cv2.imread()

第一个参数：图片名

第二个参数：

• cv2.IMREAD_COLOR : Loads a color image. Any transparency of image will be neglected. It is the default
flag.
• cv2.IMREAD_GRAYSCALE : Loads image in grayscale mode
• cv2.IMREAD_UNCHANGED : Loads image as such including alpha channel
Note: Instead of these three flags, you can simply pass integers 1, 0 or -1 respectively.

  import numpy as np
  import cv2
  img = cv2.imread('test.jpg',0) #显示一张灰度图

 显示图片

cv2.imshow()

cv2.imshow('image',img)
cv2.waitKey(0)
cv2.destroyAllWindows()

写入图片

cv2.imwrite()

cv2.imwrite('test.png',img)

打开图片，处理并保存的整个流程

import numpy as np
import cv2
img = cv2.imread('test.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('testgray.png',img)
    cv2.destroyAllWindows()