OpenCV-Python Feature2D 特征点检测 (SIFT,SURF)

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下面介绍属于nonfree的特征检测方法，如SIFT和SURF。

这些方法在opencv-contrib中，所以想要使用前，请卸载当前非contrib版本的opencv，即pip uninstall opencv-python后；再重新安装opencv-contrib-python，即pip install opencv-contrib-python

pip install -i https://pypi.tuna.tsinghua.edu.cn/simple opencv-contrib-python

SIFT Feature Detection

#!/usr/bin/env python
# -*- coding=utf-8 -*-
# Summary: 使用OpenCV3.x-Python检测SIFT特征点
# Author:  Amusi
# Date:    2018-03-17
# Reference: https://docs.opencv.org/master/d5/d3c/classcv_1_1xfeatures2d_1_1SIFT.html
 
 
import cv2
import numpy
 
 
def main():
 
 
  img = cv2.imread("lena.png")
  cv2.imshow('Input Image', img)
  cv2.waitKey(0)
  
  # 检测
  sift = cv2.xfeatures2d.SIFT_create()
  keypoints = sift.detect(img, None)
  
  # 显示
  # 必须要先初始化img2
  img2 = img.copy()
  img2 = cv2.drawKeypoints(img, keypoints, img2, color=(0,255,0))
  cv2.imwrite('sift.png', img2)
  cv2.imshow('Detected SIFT keypoints', img2)
  cv2.waitKey(0)
    
if __name__ == '__main__':
  main()

SURF Feature Detection

#!/usr/bin/env python
# -*- coding=utf-8 -*-
# Summary: 使用OpenCV3.x-Python检测SURF特征点
# Author:  Amusi
# Date:    2018-03-17
# Reference: https://docs.opencv.org/master/d5/df7/classcv_1_1xfeatures2d_1_1SURF.html
 
import cv2
import numpy
 
def main():
 
  img = cv2.imread("lena.png")
  cv2.imshow('Input Image', img)
  cv2.waitKey(0)
  
  # 检测
  surf = cv2.xfeatures2d.SURF_create()
  keypoints = surf.detect(img, None)
  
  # 显示
  # 必须要先初始化img2
  img2 = img.copy()
  img2 = cv2.drawKeypoints(img, keypoints, img2, color=(0,255,0))
  cv2.imshow('Detected SURF keypoints', img2)
  cv2.waitKey(0)
    
if __name__ == '__main__':
  main()