OpenCV is a most popular free and open-source computer vision library among students, researchers, and developers alike. It has C, C++, Python and Java interfaces and supports Windows, Linux, Mac OS, iOS, and Android. At the time of writing of this blog, the latest version of OpenCV is 3.4.0. This tutorial is designed to help you install OpenCV 3.4.0 on Ubuntu 16.04. This tutorial works for versions 2.7, 3.5 and 3.6 of python. If you want to know how to install python 3.6 on Ubuntu, check out our other tutorial Install Python 3.6 on Ubuntu.
You can install opencv by using official prebuilt pip package or build from source.
To install from official pip package:
Use following commands in a new active empty virtual environment.
To install Opencv Only:
pip install opencv-python
To add contrib package in opencv:
pip install opencv-contrib-python
To install opencv by building from source:
OpenCV can be used in python as C++ python binding. I am going to explain how to build OpenCV from source and generate python binding.
The steps needed to be taken in order to install OpenCV 3.4.0 are:
- Update and Upgrade and Cleanup (Required for error-free installation)
- Install Dependencies
- Download and Build OpenCV
Update and Upgrade and Cleanup (Required for error-free installation)
sudo apt-get update sudo apt-get upgrade
Now that we have the updates ready, we are ready to install dependencies.
sudo apt-get install build-essential sudo apt-get install cmake git libgtk2.0-dev pkg-config libavcodec-dev libavformat-dev libswscale-dev
The following command is needed to process images:
sudo apt-get install python-dev python-numpy libtbb2 libtbb-dev libjpeg-dev libpng-dev libtiff-dev libjasper-dev libdc1394-22-dev
To process videos:
sudo apt-get install libavcodec-dev libavformat-dev libswscale-dev libv4l-dev sudo apt-get install libxvidcore-dev libx264-dev
sudo apt-get install libgtk-3-dev
sudo apt-get install libatlas-base-dev gfortran pylint
To build OpenCV binding for both python 2 and 3.
sudo apt-get install python2.7-dev python3.5-dev
We are now ready to download and build OpenCV on our Ubuntu machine.
Download and Build OpenCV
To Download OpenCV 3.4.0, go to terminal and type:
wget https://github.com/opencv/opencv/archive/3.4.0.zip -O opencv-3.4.0.zip
To Download OpenCV Contrib 3.4.0 (Contrib has very useful algorithms which is a must for anyone working on Computer Vision), go to terminal and type:
wget https://github.com/opencv/opencv_contrib/archive/3.4.0.zip -O opencv_contrib-3.4.0.zip
We need to unzip to extract the zip files. Install unzip if not installed using the command:
sudo apt-get install unzip
Now extract OpenCV and OpenCV Contrib:
unzip opencv-3.4.0.zip unzip opencv_contrib-3.4.0.zip
Make a directory named build inside OpenCV-3.4.0:
cd opencv-3.4.0 mkdir build cd build
Now we are going to configure cmake:
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr/local -DOPENCV_EXTRA_MODULES_PATH=../../opencv_contrib-3.4.0/modules -DOPENCV_ENABLE_NONFREE=True ..
The command will take some time to execute. Wait for few seconds.
If the configuration is done without error, we will use make command to build.
make -j4 (where 4 is number of cores)
This command will take a few minutes to complete. On my PC, it took about 20 minutes.
Install in the location /usr/local using command
sudo make install
Reinitialize static libs using the following command
Check if the OpenCV file exists
To use OpenCV 3.4.0 in virtual environment like virtualenv, conda or any other, copy related .so file in your virtual environment python directory
Finally, check OpenCV version. Go to the terminal and type
On the python terminal, type
If you ran into any problem while installing OpenCV or have any query related to OpenCV then feel free to comment below. I will try my best to solve it.