OpenCV  4.5.1-pre
Open Source Computer Vision
Installation in Linux

Table of Contents

Next Tutorial: Using OpenCV with gcc and CMake

Original author Ana Huamán
Compatibility OpenCV >= 3.0

Quick start

Build core modules

# Install minimal prerequisites (Ubuntu 18.04 as reference)
sudo apt update && sudo apt install -y cmake g++ wget unzip
# Download and unpack sources
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
unzip opencv.zip
# Create build directory
mkdir -p build && cd build
# Configure
cmake ../opencv-master
# Build
cmake --build .

Build with opencv_contrib

# Install minimal prerequisites (Ubuntu 18.04 as reference)
sudo apt update && sudo apt install -y cmake g++ wget unzip
# Download and unpack sources
wget -O opencv.zip https://github.com/opencv/opencv/archive/master.zip
wget -O opencv_contrib.zip https://github.com/opencv/opencv_contrib/archive/master.zip
unzip opencv.zip
unzip opencv_contrib.zip
# Create build directory and switch into it
mkdir -p build && cd build
# Configure
cmake -DOPENCV_EXTRA_MODULES_PATH=../opencv_contrib-master/modules ../opencv-master
# Build
cmake --build .

Detailed process

This section provides more details of the build process and describes alternative methods and tools. Please refer to the OpenCV installation overview tutorial for general installation details and to the OpenCV configuration options reference for configuration options documentation.

Install compiler and build tools

Download sources

There are two methods of getting OpenCV sources:

Note
Snapshots of other branches, releases or commits can be found on the GitHub and the official download page.

Configure and build

Note
Configure process can download some files from the internet to satisfy library dependencies, connection failures can cause some of modules or functionalities to be turned off or behave differently. Refer to the OpenCV installation overview and OpenCV configuration options reference tutorials for details and full configuration options reference.
If you experience problems with the build process, try to clean or recreate the build directory. Changes in the configuration like disabling a dependency, modifying build scripts or switching sources to another branch are not handled very well and can result in broken workspace.
Make can run multiple compilation processes in parallel, -j<NUM> option means "run <NUM> jobs simultaneously". Ninja will automatically detect number of available processor cores and does not need -j option.

Check build results

After successful build you will find libraries in the build/lib directory and executables (test, samples, apps) in the build/bin directory:

ls bin
ls lib

CMake package files will be located in the build root:

ls OpenCVConfig*.cmake
ls OpenCVModules.cmake

Install

Warning
Installation process only copies files to predefined locations and do minor patching. Library installed using this method is not integrated into the system package registry and can not be uninstalled automatically. We do not recommend system-wide installation to regular users due to possible conflicts with system packages.

By default OpenCV will be installed to the /usr/local directory, all files will be copied to following locations:

Since /usr/local is owned by the root user, the installation should be performed with elevated privileges (sudo):

sudo make install

or

sudo ninja install

Installation root directory can be changed with CMAKE_INSTALL_PREFIX configuration parameter, e.g. -DCMAKE_INSTALL_PREFIX=$HOME/.local to install to current user's local directory. Installation layout can be changed with OPENCV_*_INSTALL_PATH parameters. See OpenCV configuration options reference for details.