vinllen@ $ pip install cv2
You are using pip version 7.1.0, however version 7.1.2 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.
Requirement already satisfied (use --upgrade to upgrade): cv2 in /usr/local/lib/python2.7/site-packages

Python 2.7.10 (default, Jul 13 2015, 12:05:58)
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named cv2
>>> import cv
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: No module named cv

pip install opencv-python

pip freeze

conda install -c https://conda.binstar.org/menpo opencv