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python-2.7opencvopencv3.0orbflann

matching error in ORB with opencv 3

currently i am working on opevcv with python but when i use 

    kp1 = orb.detect(img1,None)
    kp2 = orb.detect(img2,None)
    kp1, des1 = orb.compute(img1, kp1)
    kp2, des2 = orb.compute(img2, kp2)
    matches = matcher.match(des1, des2)

i get the error that matcher is not defined 

    matches = matcher.match(des1, des2)
    NameError: name 'matcher' is not defined

, i am using opencv 3.0.0 with python 2.7, can anyone tell me why i am getting this error ?? can we use matcher or not with python ??

Solution

  • You need to create the matcher object first. A complete example can be found on OpenCV tutorials:

    import numpy as np
import cv2
from matplotlib import pyplot as plt

img1 = cv2.imread('box.png',0)          # queryImage
img2 = cv2.imread('box_in_scene.png',0) # trainImage

# Initiate ORB detector
orb = cv2.ORB()

# find the keypoints and descriptors with ORB
kp1, des1 = orb.detectAndCompute(img1,None)
kp2, des2 = orb.detectAndCompute(img2,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(img1,kp1,img2,kp2,matches[:10], flags=2)

plt.imshow(img3),plt.show()