Extract SIFT from image using OpenCV

extract_sift.py

import cv2 # pip install opencv-contrib-python
import numpy as np # pip install numpy


# load image
img = cv2.imread('/path/to/img.jpg')

# convert to grayscale
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)

# extract SIFT feature from grayscale image
sift = cv2.xfeatures2d.SIFT_create()

# sift.detect() function finds the keypoint in the images
kp = sift.detect(gray, None)

# draws the small circles on the locations of keypoints
draw_kp = cv2.drawKeypoints(gray, kp, img, flags=cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)

# save image to file
cv2.imwrite('/path/to/img_with_sift.jpg', draw_kp)