使用python将图片改为灰度图或黑白图

import cv2
 
image = cv2.imread('./images/sunflower.jpg', cv2.IMREAD_GRAYSCALE)
cv2.imwrite('./images/gray_sunflower.jpg', image)

import cv2
 
# image = cv2.imread('./images/sunflower.jpg', cv2.IMREAD_GRAYSCALE)
 
# cv2.imwrite('./images/gray_sunflower.jpg', image)
 
#  进一步探索图片格式
image = cv2.imread('./images/sunflower.jpg')
print(image.shape)
imageGray = cv2.imread('./images/gray_sunflower.jpg')
print(imageGray.shape)
imageGray2 = cv2.imread('./images/sunflower.jpg', cv2.IMREAD_GRAYSCALE)
print(imageGray2.shape)

from PIL import Image
 
# open colour image
image_raw = Image.open("./images/sunflower.jpg")
# convert image to black and white
image_black_white = image_raw.convert('1')
image_black_white.save('./images/black_white_sunflower.jpg')
image_black_white.show()

from PIL import Image
import matplotlib.pyplot as plt
 
# open colour image
image_raw = Image.open("./images/sunflower.jpg")
image_gray = image_raw.convert('L')
# image_gray.show()
plt.figure('sunflower')  # 图名
plt.imshow(image_gray, cmap='gray')  # cmap即colormap，颜色映射
# plt.axis('off')  # 关闭网格线
plt.show()