The easiest way to install OpenCV on Windows is to simply copy the cv2.pyd file into Python's site-packages directory (e.g. C:\python27\Lib\site-packages).

To get the cv2.pyd file, download and extract the latest version of the OpenCV installation executable from http://sourceforge.net/projects/opencvlibrary/files/opencv-win/ and browse the extracted folder to find the file in the relevant build directory (e.g. build\python\x86\2.7).

try this:

Create Virtual Environment

conda create --name opencv-env python=3.6

Activate the environment

activate opencv-env

Install OpenCV and other important packages

pip install numpy scipy matplotlib scikit-learn jupyter
pip install opencv-contrib-python
pip install dlib

Test your installation

import cv2
cv2.__version__

This happens when python cannot refer to your default site-packages folder where you have kept the required python files or libraries

Add these lines in the code:

import sys

sys.path.append('/usr/local/lib/python2.7/site-packages')

or before running the python command in bash move to /usr/local/lib/python2.7/site-packages directory. This is a work around if you don't want to add any thing to the code.

Faced with the same issue on Windows 10 I downloaded the open cv binary from the Unofficial Windows Binaries for Python Extension Packages.

Search the page for opencv and for and download the correct .whl for your system. Then pip install it. By example, on my system, after opening a cmd window I typed the following.

pip install opencv_python-3.4.1-cp36-cp36m-win_amd64.whl

I then opened python and the following worked

import cv2
print(cv2.__version__)

More info is available in this Mark Jay video.

:D