Install OpenCV3-python on Mac¶

Step 1 Install Homebrew¶

If you are using an old version, you need to tap to homebrew/science.

# Homebrew recently moved popular formuale to homebrew-core
# So this is not needed anymore to install OpenCV and you can skip this step.
# tap science repo of home
brew brew tap homebrew/science

Step 2 Install Python3¶

Python 2 will be deprecated shortly in the future. Python 3 is suggested.

See Install Python 3 Via Homebrew

Step 3 Create Virtual Environment for OpenCV and Use It¶

This step is optional but strongly recommended.

See Python Virtual Environment

Step 4 Install OpenCV Via Brew¶

brew install opencv

Step 5 Add OpenCV’s site-packages path to global site-packages¶

Remember to check the paths since python is also updating.

# python 2
echo /usr/local/opt/opencv/lib/python2.7/site-packages >>
/usr/local/lib/python2.7/site-packages/opencv3.pth

# python 3
echo /usr/local/opt/opencv/lib/python3.7/site-packages >>
/usr/local/lib/python3.7/site-packages/opencv3.pth

Step 6 Make OpenCV3 Python Symlink in the Virtual Environment¶

Please double check the paths and files. I’m only showing the files and paths in my system.

# check whether the path is correct
find /usr/local/opt/opencv/lib/ -name cv2*.so

# python 2
cd ~/.virtualenvs/<envname>/lib/python2.7/site-packages/
ln -s /usr/local/opt/opencv/lib/python2.7/site-packages/cv2.so cv2.so

# python 3
cd ~/.virtualenvs/<envname>/lib/python3.7/site-packages/
ln -s /usr/local/opt/opencv/lib/python3.7/site-packages/cv2/python-3.7/cv2.cpython-37m-darwin.so cv2.so

Step 7 Test¶

# Activate virtual environment
workon <envname>

# open ipython (run this command on terminal)
ipython
# import cv2 and print version (run following commands in ipython)
import cv2
print(cv2.__version__)
# If OpenCV3 is installed correctly, above command should give output the version number
# Press CTRL+D to exit ipython