Python+OpenCV 3 - Can't use SIFT

Question

I compiled OpenCV 3 & opencv_contrib from the latest source code. I installed it into the site-packages folder for Python 2.7. I can follow all of the tutorials at http://docs.opencv.org/trunk/doc/py_tutorials/py_feature2d/py_matcher/py_matcher.html except the ones involving SIFT.

Here is the error I get:

Traceback (most recent call last):
  File "C:\Projects\icu\ex01.py", line 9, in <module>
    sift = cv2.SIFT()
AttributeError: 'module' object has no attribute 'SIFT'

Please help. I searched & searched & searched and can't find anything related to OpenCV3.

Oh, and I used Visual Studio 2013 to build it.

Answer 1

as of 3.0, SIFT, SURF, BRIEF and FREAK were moved to a seperate opencv_contrib repo.

you will have to download that, add it to your main cmake settings (please see the README there), and rebuild the main opencv repo. after 'make install' your python should have a new cv2.pyd, that contains those again. then:

# note the additional namespace:
sift = cv2.xfeatures2d.SIFT_create()