How to Install OpenCV on CentOS 8 Server

OpenCV (Open Source Computer Vision Library) is an open source computer vision library with bindings for C++, Python, and Java and supports all major operating systems. In this tutorial, we will show you how to install OpenCV on CentOS 8 system.

OpenCV can be deployed on various platforms, including Windows, Linux, Android, iOS, etc. The OpenCV installation is quite simple.

Prerequisites#

Before you start to install OpenCV on CentOS machine, you must logged in as root or sudo user.

Install OpenCV from the CentOS Repository#

By default, CentOS 8 standard repositories includes OpenCV package. Run the following command to install the OpenCV packages:

sudo dnf install opencv opencv-devel opencv-python

Verify OpenCV installation by checking version, type:

pkg-config --modversion opencv

3.4.1

Install OpenCV from the Source#

If you would prefer the latest version of OpenCV library, you can get it directly from the source. Perform the following steps to install the latest OpenCV version from the source:

1. Install dependencies#

Run the following command to install required dependencies:

sudo dnf install epel-release git gcc gcc-c++ cmake3 qt5-qtbase-devel \
python3 python3-devel python3-pip cmake python3-devel python3-numpy \
gtk2-devel libpng-devel jasper-devel openexr-devel libwebp-devel \
libjpeg-turbo-devel libtiff-devel tbb-devel libv4l-devel \
eigen3-devel freeglut-devel mesa-libGL mesa-libGL-devel \
boost boost-thread boost-devel gstreamer1-plugins-base

2. Clone repositories#

Next, clone OpenCV and OpenCV contrib repositories using following commands:

mkdir -p ~/opencv_build && cd ~/opencv_build

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

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

Currently, while writing this tutorial, the latest stable version is 4.3.0.

3. Create build directory#

Now, create a temporary build directory and navigate to inside it:

cd ~/opencv_build/opencv && mkdir build && cd build

Use the CMake command to configure the OpenCV build:

cmake3 -D CMAKE_BUILD_TYPE=RELEASE \
-D CMAKE_INSTALL_PREFIX=/usr/local \
-D INSTALL_C_EXAMPLES=ON \
-D INSTALL_PYTHON_EXAMPLES=ON \
-D OPENCV_GENERATE_PKGCONFIG=ON \
-D OPENCV_EXTRA_MODULES_PATH=~/opencv_build/opencv_contrib/modules \
-D BUILD_EXAMPLES=ON ..

It should return output as below:

-- Configuring done
-- Generating done
-- Build files have been written to: /home/vagrant/opencv_build/opencv/build

4. Start compilation#

Execute the below command to start the compilation process:

make -j4

Ensure that here in -j option you should provide number of processor as per your system. You can find number of processor by typing nproc.

Depending on your system resources, compilation process may take few minutes.

5. Install OpenCV libraries#

To install OpenCV libraries, type:

sudo make install

6. Create symlink#

Create symlink opencv4.pc file to the /usr/share/pkgconfig directory and run ldconfig to rebuild the libraries cache.

sudo ln -s /usr/local/lib64/pkgconfig/opencv4.pc /usr/share/pkgconfig/

sudo ldconfig

7. Verify installation#

pkg-config --modversion opencv4

4.3.0

Conclusion#

You successfully learned multiple ways to install OpenCV on your CentOS 8 server.

If you have any questions or feedback, feel free to comment below.