问题
Having just upgraded from opencv-2.4.11, KNearest seems to be missing
In [27]: import cv2
In [28]: print(cv2.__version__)
3.0.0-beta
In [29]: cv2.KNearest()
---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-29-d2ea29abad59> in <module>()
----> 1 cv2.KNearest()
AttributeError: 'module' object has no attribute 'KNearest'
In [30]: cv2.K
cv2.KAZE_DIFF_CHARBONNIER cv2.KAZE_DIFF_WEICKERT cv2.KMEANS_RANDOM_CENTERS cv2.KeyPoint
cv2.KAZE_DIFF_PM_G1 cv2.KAZE_create cv2.KMEANS_USE_INITIAL_LABELS cv2.KeyPoint_convert
cv2.KAZE_DIFF_PM_G2 cv2.KMEANS_PP_CENTERS cv2.KalmanFilter cv2.KeyPoint_overlap
回答1:
Many modules were removed from OpenCV core and marked as nonfree. These modules have separate repository and has to be built separately.
The repository is here https://github.com/itseez/opencv_contrib/
The info was found in this answer https://stackoverflow.com/a/27419092/892914
回答2:
In reality, KNearest has been moved to module cv2.ml in opencv3, and you have to call cv2.ml.KNearest_create() for using knn.
In [1]: import cv2
In [2]: cv2.__version__
Out[2]: '3.0.0'
In [3]: cv2.ml.KNea
cv2.ml.KNearest_BRUTE_FORCE cv2.ml.KNearest_create cv2.ml.KNearest_KDTREE
In [3]: cv2.ml.KNearest_create
For more details, please run help(cv2.ml.KNearest_create()).
Enjoy :)
来源：https://stackoverflow.com/questions/29369907/opencv-3-0-0-beta-missing-knn