[例子笔记]python3 opencv-3.0 SIFT/SURF 特征提取与匹配

参考博客
https://blog.csdn.net/Eddy_zheng/article/details/78916009

前提准备

pip install imagedt

运行代码：

# coding: utf-8
from matplotlib import pyplot as plt
from imagedt.decorator import time_cost
import cv2
print 'cv version: ', cv2.__version__


def bgr_rgb(img):
    (r, g, b) = cv2.split(img)
    return cv2.merge([b, g, r])


def orb_detect(image_a, image_b):
    # feature match
    orb = cv2.ORB_create()

    kp1, des1 = orb.detectAndCompute(image_a, None)
    kp2, des2 = orb.detectAndCompute(image_b, None)

    # create BFMatcher object
    bf = cv2.BFMatcher(cv2.NORM_HAMMING, crossCheck=True)

    # Match descriptors.
    matches = bf.match(des1, des2)

    # Sort them in the order of their distance.
    matches = sorted(matches, key=lambda x: x.distance)

    # Draw first 10 matches.
    img3 = cv2.drawMatches(image_a, kp1, image_b, kp2, matches[:100], None, flags=2)

    return bgr_rgb(img3)

@time_cost
def sift_detect(img1, img2, detector='surf'):
    if detector.startswith('si'):
        print "sift detector......"
        sift = cv2.xfeatures2d.SURF_create()
    else:
        print "surf detector......"
        sift = cv2.xfeatures2d.SURF_create()

    # find the keypoints and descriptors with SIFT
    kp1, des1 = sift.detectAndCompute(img1, None)
    kp2, des2 = sift.detectAndCompute(img2, None)

    # BFMatcher with default params
    bf = cv2.BFMatcher()
    matches = bf.knnMatch(des1, des2, k=2)

    # Apply ratio test
    good = [[m] for m, n in matches if m.distance < 0.5 * n.distance]

    # cv2.drawMatchesKnn expects list of lists as matches.
    img3 = cv2.drawMatchesKnn(img1, kp1, img2, kp2, good, None, flags=2)

    return bgr_rgb(img3)


if __name__ == "__main__":
    # load image
    image_a = cv2.imread('./img1.jpg')
    image_b = cv2.imread('./img2.png')

    # ORB
    # img = orb_detect(image_a, image_b)

    # SIFT or SURF
    img = sift_detect(image_a, image_b)

    plt.imshow(img)
    plt.show()
--------------------- 
作者：Eddy_zheng 
来源：CSDN 
原文：https://blog.csdn.net/Eddy_zheng/article/details/78916009 

问题解决：
1.

SyntaxError: Missing parentheses in call to 'print'. Did you mean print('cv version: ', cv2.__version__)?

在p3.6下所有print加括号
2.

   import cPickle

ModuleNotFoundError: No module named 'cPickle'

python2有cPickle，但是在python3下，是没有cPickle的；
解决办法：将cPickle改为pickle

import pickle

  File "F:/SIFT_SURF_1pic.py", line 51, in sift_detect
    kp1, des1 = sift.detectAndCompute(img1, None)

error: OpenCV(3.4.2) C:\Miniconda3\conda-bld\opencv-suite_1534379934306\work\opencv_contrib-3.4.2\modules\xfeatures2d\src\surf.cpp:892: error: (-215:Assertion failed) !_img.empty() && ((imgtype) & ((1 << 3) - 1)) == 0 && (imgcn == 1 || imgcn == 3 || imgcn == 4) in function 'cv::xfeatures2d::SURF_Impl::detectAndCompute'

这个就是说你这行代码下的读取图片是空的

    image_a = cv2.imread('./img1.jpg')
    image_b = cv2.imread('./img2.png')

只要把图片放到你这个.py文件保存的路径下即可，子文件夹不可以

img1:

img2:

最后结果;