Hands-on ML Projects with OpenCV: Master Computer Vision and Machine Learning using OpenCV and Python

CHAPTER 1

Getting Started With OpenCV

Introduction

This chapter will cover a detailed introduction to computer vision and OpenCV and their practical application in real-time, and then finally a complete explanation of installation procedures.

Structure

In this chapter, we will cover the following topics:

Introduction to Computer Vision

Introduction to OpenCV

Benefits of learning OpenCV

OpenCV real-time applications in computer vision

OpenCV architecture and explanation

Features of OpenCV Library

Python Code Editors for OpenCV

Downloading and Installing OpenCV

Windows

Mac

Google colab for OpenCV

Introduction to Computer Vision

Computer vision is a field of computer science that uses artificial intelligence and machine learning algorithms to process digital images and videos. It is a subset of artificial intelligence that focuses on giving computers the ability to understand and interpret the visual world. Computer vision algorithms can be used to detect objects, identify faces, recognize patterns, classify images, segment images into meaningful parts, and more.

Computer vision is used in many fields such as robotics, medical imaging, driverless cars, facial recognition, and industrial inspection. By applying computer vision algorithms to digital images and videos, machines can gain an understanding of the content of the image or video. This understanding can then be used to make decisions or guide actions.

Computer vision algorithms can be divided into two categories:

Low-level algorithms: It is focused on analyzing the pixels of an image to detect basic shapes and patterns, such as lines and curves.

High-level algorithms: It is used to identify objects or recognize complex structures.

The process of computer vision usually starts with a set of images or videos as input. The images or videos are then pre-processed to improve the quality of the data. This is followed by feature extraction, which involves extracting meaningful information from images or videos. Finally, the extracted features are used to train the computer vision algorithms.

Computer vision has been widely used in many applications such as medical imaging, robotics, surveillance, facial recognition, and augmented reality. In medical imaging, computer vision algorithms are used to detect tumors, diagnose diseases, and measure vital signs. In robotics, computer vision algorithms are used to recognize objects and navigate around obstacles.

In surveillance, computer vision algorithms are used to detect suspicious activities. In facial recognition, computer vision algorithms are used to identify and classify people. In augmented reality, computer vision algorithms are used to display virtual objects in real-world environments.

Introduction to OpenCV

OpenCV (Open-Source Computer Vision Library) is an open-source computer vision library. It was originally developed by Intel Corporation in 1999 and later became a collaborative effort of several companies and universities. It is written in C++ and supports many programming languages.

OpenCV is an open-source computer vision and machine learning software library, and its main goal is real-time computer vision applications. It was built to provide a good infrastructure for computer vision applications and to improve the use of machine vision in commercial products.

OpenCV library has more than 2500 optimized algorithms and has a modular structure, which means that the package includes several shared or static libraries, and developers can pick and choose which parts they wish to use. For example, OpenCV includes numerous features, such as pattern recognition, motion detection, and object identification. OpenCV can be used in a wide variety of applications and platforms, including embedded systems, robotics, mobile phones, video surveillance, and computer vision. Its code is portable, and it is suitable for real-time applications. OpenCV is also available as a library of optimized functions in various programming languages.

OpenCV has become the go-to library for computer vision and machine learning. It is being used in many industries, such as medical, automotive, retail, and robotics, to develop applications that can recognize objects, analyze images, and extract useful data from them. This can be used in 3D point clouds from stereo cameras, stitch images together to produce a high-resolution image of an entire scene, find similar images from an image database, and much more.

OpenCV is open-source and free to use, so developers can access and modify its source code according to their needs. The library is constantly updated with new algorithms and features, making it a powerful and constantly evolving library.

Benefits of Learning OpenCV

Learning OpenCV can have tremendous benefits for a wide variety of users. OpenCV is a powerful open-source library providing easy access to both basic and advanced computer vision techniques, allowing developers to create applications quickly and easily. This can be used to create several different applications, from simple games to complex AI-driven applications.

OpenCV is the vast number of resources available to the user. OpenCV has an extensive library of tools and tutorials that can help new developers become comfortable with the language, and advanced users quickly create complex applications. OpenCV also has a wide range of example projects, which can serve as great starting points for learning.

Let us discuss the major benefits of learning OpenCV Library:

Versatility: OpenCV can be used for a wide variety of tasks, such as object tracking, facial recognition, motion detection, and more. This is extremely valuable, as it allows developers to create a wide range of applications without having to learn multiple languages and frameworks.

Compatibility: OpenCV can be used with a wide variety of languages and frameworks, such as Python, C++, Java, and even the popular .NET Framework. This is extremely useful, as it allows developers to interact with different platforms quickly and easily, without having to learn multiple languages.

Deep learning: OpenCV has many tools and APIs that make it easy to integrate deep learning algorithms into applications. This can be used to create AI-driven applications that can harness the power of machine learning, such as facial recognition, object detection, and so on.

Scalability: OpenCV is designed to work with large amounts of data and can easily handle large datasets, allowing developers to quickly and easily develop applications that can quickly and accurately process huge amounts of data.

Opportunities for developers: OpenCV is a very popular language, and there is a wide range of jobs that require knowledge of OpenCV. Many companies are looking for developers with OpenCV skills, and these jobs can be quite lucrative.

In summary, learning OpenCV can have tremendous benefits for a wide variety of users. OpenCV is a powerful open-source library providing easy access to both basic and advanced computer vision techniques, allowing developers to create applications.

Furthermore, OpenCV is versatile, compatible, supports deep learning, and is extremely scalable. Finally, learning OpenCV can open up a world of opportunities for developers, as knowledge of OpenCV is highly valued in the job market.

OpenCV Real-time Applications in Computer Vision

OpenCV is an open-source computer vision library that provides real-time applications for vision-based operations. OpenCV provides several powerful tools for image processing and computer vision research, including a feature detection and tracking library, a real-time gesture recognition system, and a computer vision-enabled language recognition library.

OpenCV offers high speed and accuracy for identifying objects in photographs, videos, and other digital images. It can detect faces, identify features and characteristics, read text from images, and recognize objects. Let us now discuss examples of real-time applications in computer vision using OpenCV Library:

Image and video processing: OpenCV provides a wide range of functions for image and video processing, such as image filtering, segmentation, and feature extraction.

Medical imaging: OpenCV can be used to analyze medical images, such as X-rays and MRI scans, to assist with diagnosis and treatment.

Object detection and recognition: OpenCV provides tools for detecting and recognizing objects in images and videos, including face detection, pedestrian detection, and object recognition.

Video surveillance: OpenCV can be used to develop video surveillance systems, including motion detection and tracking.

Augmented reality: OpenCV can be used to create augmented reality applications that overlay virtual objects onto the real world.

Robotics: OpenCV can be used to develop algorithms for robots to navigate and interact with their environment, including obstacle detection and avoidance.

Autonomous vehicles: OpenCV can be used to develop algorithms for autonomous vehicles, such as lane detection and object detection. It is also used to build similar products like Google street view and helps compete in challenges like the DARPA.

Gaming: OpenCV can be used to create interactive games that use gestures and facial expressions as input.

Space: OpenCV has been used for some of the most high-profile projects like space exploration. It was used in the Curiosity rover mission to Mars to help the rover navigate and avoid obstacles. The rover used a combination of stereo cameras and OpenCV algorithms to create 3D maps of the terrain and identify potential hazards.

These are just a few examples of the many applications of OpenCV. With its wide range of functions and algorithms, OpenCV is a powerful tool for developing computer vision and machine learning applications.

OpenCV Architecture and Explanation

OpenCV architecture is divided into several components that work together to provide a comprehensive framework for image and video processing. Here are the main components of the OpenCV architecture:

Core Functionality: This is the core of the OpenCV library and includes basic data structures, mathematical functions, and algorithms for image processing. It provides support for basic image operations such as image conversion, filtering, and morphological operations.

High-Level GUI: This component provides high-level graphical user interface functionality and includes functions for creating windows, displaying images, and handling mouse and keyboard events.

Video I/O: This component provides support for reading and writing video files in various formats. It also provides functions for capturing video from cameras and other sources.

Image Processing: This component includes a wide range of image processing algorithms, such as edge detection, image segmentation, object detection, and feature detection. It also provides support for image transformations, such as scaling, rotation, and affine transformations.

Feature Detection and Description: This component provides functions for detecting and describing image features, such as corners, blobs, and edges. It also includes algorithms for matching features between images, which are useful for tasks such as object recognition and tracking.

Object Detection and Recognition: This component provides support for object detection and recognition, using techniques such as Haar cascades, HOG features, and deep learning-based methods.

Machine Learning: OpenCV includes several machine learning algorithms, such as decision trees, support vector machines, and neural networks. These algorithms can be used for tasks such as classification, regression, and clustering.

Miscellaneous: This component includes various other functions and algorithms, such as camera calibration, stereo vision, optical flow, and 3D reconstruction.

Overall, the OpenCV architecture provides a comprehensive framework for image and video processing and includes a wide range of functions and algorithms that can be used for a variety of applications.

Features of OpenCV Library

OpenCV is a powerful library for image and video processing, and it comes with a wide range of features that make it a popular choice for developers and researchers. Here are some of the key features of OpenCV:

Cross-platform: OpenCV is available on multiple platforms, including Windows, Linux, Mac OS, and Android.

Efficient: OpenCV is optimized for performance, with functions that are written in C/C++ for speed and efficiency.

Large collection of functions: OpenCV includes a large collection of functions and algorithms for image and video processing, including basic image operations, feature detection, object recognition, machine learning, and more.

Support for multiple programming languages: OpenCV supports multiple programming languages, including Python, C/C++, Java, and MATLAB.

High-level GUI: OpenCV provides a high-level graphical user interface (GUI) for displaying images and videos, creating windows, and handling user input.

Camera calibration: OpenCV includes functions for camera calibration, which is important for tasks such as 3D reconstruction and stereo vision.

Support for multiple file formats: OpenCV supports multiple file formats for reading and writing images and videos, including JPEG, PNG, TIFF, AVI, and MP4.

Open source: OpenCV is an open-source library, which means that developers can use, modify, and redistribute the code without restriction.

Overall, the features of OpenCV make it a powerful tool for image and video processing, and it is widely used in research, industry, and education.

Python Code Editors for OpenCV

There are many Python code editors available that can be used for developing OpenCV applications. Here are some popular ones:

Visual Studio Code: Visual Studio Code is a lightweight code editor that is highly extensible through plugins. This includes support for Python development and has several plugins available for OpenCV development. It includes features such as syntax highlighting, code completion, and an integrated Terminal.

Jupyter Notebook: Jupyter Notebook is a web-based interactive environment for running Python code, and it includes support for OpenCV development. It provides an easy way to experiment with OpenCV code and visualize the output in real-time. It also allows for the creation of interactive documents that can be shared with others.

PyCharm: PyCharm is a powerful IDE for Python development, and it includes features specifically designed for OpenCV development. It includes an interactive debugger, a code editor with syntax highlighting and autocomplete, and integration with Git for version control. PyCharm also provides support for Jupyter notebooks, which can be used for experimenting with OpenCV code.

Spyder: Spyder is an open-source IDE for scientific Python development that includes a code editor, interactive console, and several other tools for data analysis and visualization. It also includes support for OpenCV development through the use of the QtConsole, which provides a graphical interface for running Python code and displaying OpenCV output.

Sublime Text: Sublime Text is a lightweight code editor that is highly customizable and extensible through plugins. This includes support for Python development and has several plugins available for OpenCV development. It includes features such as syntax highlighting, code completion, and an integrated Terminal.

These are just a few examples of the many code editors available for developing OpenCV applications in Python. The choice of editor depends on personal preference, project requirements, and development style.

Downloading and Installing OpenCV for Windows

Here are the steps to download and install Anaconda on Windows and open Jupyter Notebook:

Download Anaconda: Go to the Anaconda website at https://www.anaconda.com/products/individual and scroll down to the bottom of the page and download the latest version of Anaconda for Windows.

Choose the version that matches your system architecture (32-bit or 64-bit) and your version of Python.

The following figure represents the available Anaconda versions for all operating systems:

Figure 1.1: Available Anaconda versions

Install Anaconda: Double-click on the downloaded Anaconda installer and follow the instructions to install Anaconda on your system. You can accept the default settings unless you have a specific reason to change them.

Open Jupyter Notebook: Once Anaconda is installed, open the Anaconda Navigator application. You should be able to find it in the Start menu or by searching for Anaconda Navigator in the Windows search bar. The following figure is an example of the Anaconda Navigator page:

Figure 1.2: Available IDE in Anaconda Navigator

Launch Jupyter Notebook: In the Anaconda Navigator, click on the Launch button under the Jupyter Notebook icon. This will open a new tab in your default web browser with the Jupyter Notebook interface.

Create a new notebook: To create a new notebook, click the New button on the right-hand side of the Jupyter Notebook interface and select Python 3 (or another kernel, if you prefer). This will create a new notebook with an empty code cell. Refer to the image below:

Figure 1.3: New Jupyter Notebook interface

Type in the following command and press Shift + Enter:

! pip install opencv-python

Refer to the following figure for the new notebook page:

Figure 1.4: Installation of OpenCV in Jupyter Notebook

Import OpenCV: To import OpenCV into your notebook, enter the following code in a new cell and run it:

import cv2

print(cv2.__version__)

Refer to the following figure to check the Version of OpenCV:

Figure 1.5: OpenCV successfully installed

This should display the version of OpenCV that you have installed.

You have successfully installed Anaconda on your Windows system and are ready to start using Jupyter Notebook to write and run OpenCV code.

Downloading and Installing OpenCV for MacOS

Here are the steps to download and install Anaconda on macOS and open Jupyter Notebook:

Download Anaconda: Go to the Anaconda website at https://www.anaconda.com/products/individual and download the latest version of Anaconda for macOS.

Choose the version that matches your system architecture (32-bit or 64-bit) and your version of Python. (Refer to Figure 1.1):

Install Anaconda: Double-click on the downloaded Anaconda installer and follow the instructions to install Anaconda on your system. You can accept the default settings unless you have a specific reason to change them.

Open Terminal: To open the Terminal app, go to the Applications folder, then to the Utilities folder, and click Terminal.

Launch Jupyter Notebook: In the Terminal window, type the following command and press Enter: (Refer to Figure 1.3):

jupyter notebook

This will start the Jupyter Notebook server and open a new tab in your default web browser with the Jupyter Notebook interface.

Create a new notebook: To create a new notebook, click the New button on the right-hand side of the Jupyter Notebook interface and select Python 3 (or another kernel, if you prefer). This will create a new notebook with an empty code cell.

Type in the following command and press Shift + Enter: (Refer to Figure 1.4):

! pip install opencv-python

Import OpenCV: To import OpenCV into your notebook, enter the following code in a new cell and run it: (Refer to Figure 1.5)

import cv2

print(cv2.__version__)

This should display the version of OpenCV that you have installed.

You have successfully installed your macOS system and are ready to start using Jupyter Notebook to write and run OpenCV code.

Google Colab for OpenCV

Google Colab is a free cloud-based platform that provides a Jupyter Notebook environment to run Python code. It has the advantage of providing free access to high-performance computing resources.

Google Colab provides a powerful platform for developing OpenCV applications, and it can be used for a wide range of tasks, such as image and video processing, object detection, and machine learning.

To use Google Colab for OpenCV, follow these steps:

Open Google Colab: Go to https://colab.research.google.com/ and sign in with your Google account.

Create a new notebook: Click on New Notebook to create a new notebook. You can choose to create a blank notebook or use one of the available templates. Refer to the following Figure 1.6:

Figure 1.6: Home page for Google colab

Install OpenCV: To install OpenCV, run the following command in a new code cell:

!pip install opencv-python

The following figure represents the new Colab notebook:

Figure 1.7: Installation of OpenCV in Google colab

This will download and install