from PIL import Image
import numpy as np
im = Image.open("/home/lw/a.jpg")
im.show()
img = np.array(im) # image类 转 numpy
img = img[:,:,0] #第1通道
im=Image.fromarray(img) # numpy 转 image类
im.show() 转载https://blog.csdn.net/liuweizj12/article/details/80221537