4.Installing OpenCV 3 Package

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 I am using a Raspberry Pi V3 updated to the last version of Raspbian (Stretch), so the best way to have OpenCV installed, is to follow the excellent tutorial developed by Adrian Rosebrock: Raspbian Stretch: Install OpenCV 3.

I tried several different guides to install OpenCV on my Pi. Adrian’s tutorial is the best. I advise you to do the same, following his guideline step-by-step.

Once you finished Adrian’s tutorial, you should have an OpenCV virtual environment ready to run our experiments on your Pi.

Let’s go to our virtual environment and confirm that OpenCV 3 is correctly installed.

Adrian recommends run the command “source” each time you open up a new terminal to ensure your system variables have been set up correctly.

source ~/.profile

Next, let’s enter on our virtual environment:

workon cv

If you see the text (cv) preceding your prompt, then you are in the cv virtualenvironment:

(cv) pi@raspberry:~$

Adrian calls the attention that the cv Python virtual environment is entirely independent and sequestered from the default Python version included in the download of Raspbian Stretch. So, any Python packages in the global site-packages directory will not be available to the cv virtual environment. Similarly, any Python packages installed in site-packages of cv will not be available to the global install of Python.

Now, enter in your Python interpreter:

python

and confirm that you are running the 3.5 (or above) version.

Inside the interpreter (the “>>>” will appear), import the OpenCV library:

import cv2

If no error messages appear, the OpenCV is correctly installed ON YOUR PYTHON VIRTUAL ENVIRONMENT.

You can also check the OpenCV version installed:

cv2.__version__

The 3.3.0 should appear (or a superior version that can be released in future).

The above Terminal PrintScreen shows the previous steps.




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