text: import cv2
  import numpy as np
  import matplotlib.pyplot as plt
  
  img = cv2.imread("chessboard.jpg")
  sift = cv2.xfeatures2d.SIFT_create()
  (kp, des) = sift.detectAndCompute(cv2.cvtColor(img, cv2.COLOR_BGR2GRAY), None)
  plt.imshow(cv2.drawKeypoints(img, kp, None))
  plt.show()