Install OpenCV C C++ in Ubuntu 18.04 LTS : Step by Step Guide

Install OpenCV in Ubuntu 18.04

Keywords: OpenCV, Ubuntu

OpenCV (Open Source Computer Vision Library) is an open source computer vision and machine learning software library. OpenCV can be used to detect and recognize faces, identify objects, classify human actions in videos, track camera movements, track moving objects etc. To know more about OpenCV visit

Please follow steps mentioned in this post to install OpenCV in Ubuntu 18.04 (LTS). All the terminal commands are summarized in the end of the post and you can access the same by clicking  here.

Step 1. Update the Ubuntu System Package

Open the terminal and Run command to update Ubuntu system package index.

Run commands one by one.

Step 2. Install Required tools and packages

If you encounter error like below screenshot, then follow the step 2.a

if you encounter error like below screenshot, then follow the step 2.b

Step 2.a Add repository and ppa

Step 2.b Add repository and ppa

Step 3. Download OpenCV Sources using git

We need to clone the OpenCV sources using “git” to build and install it. We will download the source in /opt/ directory. Downloading, building and installation process requires root permission. Execute the commands to proceed further.

Step 4. Build & Install OpenCV

Execute the commands one by one:

Step 5. Check OpenCV version installed

Run the command in terminal

If you encounter error like “pakage opencv not found” then follow step 5.a.

Step 5.a. Find & Set “opencv.pc” file path

Run the command in terminal

Step 6. Compile & Run a Test Program 

Create a directory and put 1 sample image in it. Create a .cpp file and copy and paste the code posted here.

Change the image name & extension (.jpeg/.png etc). Compile and Run the program.

(A) Make a directory and .cpp file

(B)Copy the below code and paste in the file just created

(C) Compile the Code

(D) Execute the Code

Command Summary

This is the summary of all commands needed to install OpenCV in Ubuntu. If you encounter any problem during installation please check the respective Step. You might get the resolution in the post itself as I have also covered the problem & resolution of the errors I faced during the installation.

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Note: Logo of OpenCV & Ubuntu used are the property of OpenCV & Ubuntu respectively.

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