Python计算机视觉SIFT尺度不变的图像特征变换

import cv2  #opencv 读取进来为BGR格式
import matplotlib.pyplot as plt
import numpy as np
#一个魔法指令，不需要采用plt.show()显示图像
%matplotlib inline   
print(cv2.__version__)   # 3.4.1.15 pip install opencv-python ==3.4.1.15  pip install opencv-contrib-Python==3.4.1.15
def cv_show(name,img):
    cv2.imshow(name,img)
    cv2.waiTKEy(0)
    cv2.destroyAllwindows()
img = cv2.imread('images/test2.jpg')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
cv_show('gray',gray)
#得到特征点
sift = cv2.xfeatures2d.SIFT_create()
kp = sift.detect(gray,None)
img = cv2.drawKeypoints(gray,kp,img)
cv_show('keyPoint',img)
# 计算特征
kp, des = sift.compute(gray, kp)
print(np.array(kp).shape)
print(des.shape)
print(des[0])