import cv2
import numpy as np

# 灰度 0-255 255-当前灰度值
img = cv2.imread('image0.jpg', 1)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

dst = np.zeros((height, width, 1), np.uint8)

for i in range(height):
  for j in range(width):
    grayPixel = 255 - gray[i, j]
    dst[i, j] = grayPixel

cv2.imshow('image', dst)
cv2.waitKey(0)

import cv2
import numpy as np

img = cv2.imread('image0.jpg', 1)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]

dst = np.zeros((height, width, 3), np.uint8)

for i in range(height):
  for j in range(width):
    (b, g, r) = img[i, j]
    b = 255 - b
    g = 255 - g
    r = 255 - r
    dst[i, j] = (b, g, r)


cv2.imshow('image', dst)
cv2.waitKey(0)