OpenCV is a powerful and versatile library widely used for real-time computer vision tasks. It’s commonly used in applications like image and video processing, object detection, facial recognition, and more. Recent versions of Ubuntu come with pre-built OpenCV packages available through the apt package manager.

For some reason, if you prefer a different version than what’s available in the repositories, or you’re using an older version of Ubuntu that doesn’t have OpenCV pre-built in it’s repository, in this article we will discuss two methods for installing OpenCV in Ubuntu.

1. Install OpenCV in Ubuntu using APT package manager

Step 1 : Update Package List

To make sure we are getting the latest version of OpenCV, update the package list using apt update command.

sudo apt update -y

updating packages

Step 2: Install OpenCV

Once repositories are up to date, we will install opencv using apt install command.

sudo apt install python3-opencv

installing opencv using APT Package manager

Step 3 : Verify installation

Once, installation is done, verify installation using print(cv2.__version__) command in python shell.

To open python shell, first type python3 in your terminal.

python3

Once python3 shell is opened, print version number of opencv using following command.

import cv2
print(cv2.__version__)

verifying installation

2. Install OpenCV in Ubuntu by Compiling from sources

Step 1 : Installing dependencies

In order to install opencv from github source, we will need to download required dependencies using apt install command as follows

sudo apt install build-essential cmake wget unzip git -y

installing build dependencies

Step 2 : download opencv source

In this step, we will download official source code from opencv github page using git clone command.

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

cloning opencv sources from github

Step 3 : Navigate to opencv directory and making configuration

Once repo is cloned, navigate to cloned directory using cd command.

cd  opencv

Now create build directory for compiling sources using mkdir command and navigate to it using cd command.

mkdir build
cd build

creating and navigating to build directory

Step 4: Compiling and building packages for installation

Once we are in build directory, use cmake command to start compiling build files for installation.

cmake ../

compiling source code

Once compilation is done, we will make build packages using make command.

make

building package using “make”

Step 5: Installing openCV

After packages are built, install it using make install command.

sudo make install

installing opencv using make install command

Step 6 : Verify installation

Once, installation is done, verify installation using print(cv2.__version__) command in python shell.

To open python shell, first type python3 in your terminal.

python3

Once python3 shell is opened, print version number of opencv using following command.

import cv2
print(cv2.__version__)

verifying installation

How to install opencv in Ubuntu? – FAQs

What is OpenCV?

OpenCV (Open Source Computer Vision Library) is a powerful library for real-time computer vision tasks. It is useful for image processing, object detection, facial recognition, and many other vision applications.

What are the benefits of using APT for OpenCV installation?

• Easier installation
• Ensured compatibility with your system
• Regular security updates

How do I keep OpenCV updated?

If you used Method 1, simply run sudo apt update && sudo apt upgrade regularly. For Method 2, download the latest source code, recompile, and install.

Conclusion

In this article, we’ve discussed two methods for installing OpenCV on Ubuntu. For most users, the recommended approach is to use the Ubuntu repositories (using APT package manager) due to its ease of installation, compatibility with system, and access to regular security updates. However, if you require a specific version not available in the repositories, or need to install a latest development version, compiling OpenCV from source can be a suitable alternative.