How to install OpenCV on Ubuntu 20.04

 The OpenCV is used for a wide range of applications. Some of them are medical image analysis, surveillance video, detecting, extracting 3D models, and many more. Let’s install OpenCV on ubuntu 20.04 in two different ways.

From this blog, you will get an apparent view regarding the installation and configuration of openCV on ubuntu 20.04 as a part of our server management plan. You can also take assistance from our technical team support 24/7 for further Migration and configuration. 

Installing OpenCV on Ubuntu 20.04

You can install OpenCV by using two different methods.

• Using Ubuntu repository
• Through the source

Install OpenCV from the Ubuntu Repository

From the Default Ubuntu20.04 repositories you can install the OpenCV.Run the command.

$ sudo apt update
$ sudo apt install libopencv-dev python3-opencv

All packages are necessary to run OpenCV.

 Verify the installation by importing the cv2 module and printing the OpenCV version:

$ python3 -c “import cv2; print(cv2.__version__)"

Output

4.2.0

This displaces the 42.0 OpenCV version. 

Install OpenCV from the Source

Building the OpenCV library from the source where you can optimize the latest version for your particular system. you have complete control over the build options.

Follow the steps to install the latest OpenCV version from the source.

Install the build tools and dependencies:

$ sudo apt install build-essential cmake git pkg-config libgtk-3-dev \
libavcodec-dev libavformat-dev libswscale-dev libv4l-dev \
libxvidcore-dev libx264-dev libjpeg-dev libpng-dev libtiff-dev \
gfortran openexr libatlas-base-dev python3-dev python3-numpy \
libtbb2 libtbb-dev libdc1394-22-dev libopenexr-dev \
libgstreamer-plugins-base1.0-dev libgstreamer1.0-dev

Clone the OpenCV’s and OpenCV contrib repositories:

$ mkdir ~/opencv_build && cd ~/opencv_build
$ git clone https://github.com/opencv/opencv.git
$ git clone https://github.com/opencv/opencv_contrib.git

For an older version of OpenCV, cd to both OpenCV and opencv_contrib directories and run git checkout <opencv-version>

Once done, create a temporary build directory and navigate to it:

$ cd ~/opencv_build/opencv
$ mkdir -p build && cd build

Set up the OpenCV build with CMake:

$ cmake -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 ..

Output

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

Start the compilation process:

$ make -j8

Initially, we modify the -j flag according to the processor. To find the number of cores in the processor, type nproc.

Wait for the compilation to finish.

Install OpenCV:

$ sudo make install

In order to verify, type the following commands.

C++ bindings:
$ pkg-config –modversion opencv4

Output

4.3.0
Python bindings:
python3 -c “import cv2; print(cv2.__version__)”
Output
4.3.0-dev

• Pip Install OpenCV For Desktop Environments

To install OpenCV, run:

$ pip3 install opencv-python
$ sudo pip3 install scikit-build
$ sudo pip3 install cmake
$ sudo pip3 install opencv-python

open-cv python will install only main modules. However, to install both main and contrib modules, run:

$ sudo pip3 install opencv-contrib-python

Pip install OpenCV For Server (headless) Environments

To install for headless environments where there is no GUI available, run:

For main modules only:

$ sudo pip3 install opencv-python-headless

For both main and contrib modules:

$ sudo pip3 install opencv-contrib-python-headless

To verify installation, invoke Python3 console and run:

$ import csv2

Error while installing OpenCV on Ubuntu 20.04

Error: ModuleNotFoundError: No module named ‘skbuild’

In order to resolve this, we make sure that Pip is the latest. If not, update Pip.

Eventually, run the following commands:

$ sudo pip3 install scikit-build
$ sudo pip3 install cmake
$ sudo pip3 install opencv-python

Conclusion

In short, you can install the OpenCV on ubuntu 20.04 in two different ways. you can also take our technical team support to install OpenCV from the source on your behalf.