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cat /etc/debian_version
lsb_release -a

Install OpenCV

RaspberryPi4 (& zero) + Raspbian buster

sudo apt install python3-opencv

Old?

Follow this website

#### Step #2
sudo apt-get update && sudo apt-get upgrade

sudo apt-get install build-essential cmake pkg-config

sudo apt-get install libjpeg-dev libtiff5-dev libjasper-dev libpng-dev

sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev
sudo apt-get install libxvidcore-dev libx264-dev

sudo apt-get install libfontconfig1-dev libcairo2-dev
sudo apt-get install libgdk-pixbuf2.0-dev libpango1.0-dev
sudo apt-get install libgtk2.0-dev libgtk-3-dev

sudo apt-get install libatlas-base-dev gfortran

sudo apt-get install libhdf5-dev libhdf5-serial-dev libhdf5-103
sudo apt-get install libqtgui4 libqtwebkit4 libqt4-test python3-pyqt5

sudo apt-get install python3-dev

#### Step #3
....
#### Step #4a
....

If error occurred in making environment... ( sudo nano /usr/local/bin/virtualenvwrapper.sh )

....
#VIRTUALENVWRAPPER_ENV_BIN_DIR="usr/local/bin"
VIRTUALENVWRAPPER_ENV_BIN_DIR="bin"
....

If can't use Webcam...

sudo apt-get install fswebcam

If always you want to use the environment created... ( nano ~/.bashrc )

workon cv