How to Install OpenCV on Ubuntu 18.04

How to Install OpenCV on Ubuntu 18.04. In this guide you are going to learn how to setup OpenCV (Open Source Computer Vision Library). OpenCV is an open-source highly optimized library with focus on real-time applications and has a wide range of support for C++, Python and Java interfaces support Linux, MacOS, Windows, iOS, and Android.

The library has more than 2500 optimized algorithms for computer vision and machine learning to detect and recognize faces, identify objects, classify human actions in videos, track camera movements and many more.

This setup is tested on Google Cloud, it will work on other cloud services like AWS, Azure and on any VPS or dedicated servers running Ubuntu 18.04.

Initial setup

Start by updating the package index and upgrading the packages to the latest available version.

sudo apt update
sudo apt upgrade

Install OpenCV from Repository

OpenCV is available by default in the Ubuntu repositories. If you are just using OpenCV for programming and development purposes you can follow this method. Otherwise you need to install OpenCV from source. You can see this guide just below this method.

To install OpenCV with Python3 you can execute the following command in your terminal.

sudo apt install python3-opencv

To install OpenCV with Python2 you can execute this command instead of the previous one.

sudo apt install python-opencv

Just wait for the installation to complete and verify the installation using the following command.

python3 -c "import cv2; print(cv2.>version)"

This command will output the installed version of OpenCV. At the time of writing the OpenCV version installed is 3.2.0.

Output
3.2.0

Install OpenCV from Source

Installing OpenCV from source is the recommended method to install OpenCV to get control over the full installation.

Follow to below mentioned steps to install OpenCV from source.

Start by installing cmake for configuring and gcc for compiling.

sudo apt install git cmake gcc g++

Install Python-devel and Numpy for building Python bindings.

sudo apt install python3-dev python3-numpy

If you wish to install with Python2 you can try use the following command instead of the previous one.

sudo apt install python-dev python-numpy

Now you need GTK support for GUI features, Camera, Media and others.

sudo apt install libavcodec-dev libavformat-dev libswscale-dev libgstreamer-plugins-base1.0-dev libgstreamer1.0-dev

For GTK 3 support use the following command.

sudo apt install libgtk-3-dev

For GTK 2 support, follow this instead the one before.

sudo apt install libgtk2.0-dev

These are the required packages to install OpenCV from source.

Now you can download OpenCV from using git.

git clone https://github.com/opencv/opencv.git

This command will download the latest stable version of OpenCV inside a opencv folder.

Navigate inside the opencv folder.

cd opencv

Create a new build directory and navigate inside the directory.

mkdir build && cd build

Configure OpenCV library using cmake command.

cmake ../

Now you can build the files using make command and install it using make install command

make
sudo make install

Once the installation is completed, you can verify it using the following command.

pkg-config --modversion opencv4

Output
4.2.0

Conclusion

Now you have learned how to install OpenCV on Ubuntu 18.04 from repository and also build from source.

Thanks for your time. If you face any problem or any feedback, please leave a comment below.