Book Image

Learn OpenCV 4 By Building Projects - Second Edition

By : David Millán Escrivá, Vinícius G. Mendonça, Prateek Joshi
Book Image

Learn OpenCV 4 By Building Projects - Second Edition

By: David Millán Escrivá, Vinícius G. Mendonça, Prateek Joshi

Overview of this book

OpenCV is one of the best open source libraries available, and can help you focus on constructing complete projects on image processing, motion detection, and image segmentation. Whether you’re completely new to computer vision, or have a basic understanding of its concepts, Learn OpenCV 4 by Building Projects – Second edition will be your guide to understanding OpenCV concepts and algorithms through real-world examples and projects. You’ll begin with the installation of OpenCV and the basics of image processing. Then, you’ll cover user interfaces and get deeper into image processing. As you progress through the book, you'll learn complex computer vision algorithms and explore machine learning and face detection. The book then guides you in creating optical flow video analysis and background subtraction in complex scenes. In the concluding chapters, you'll also learn about text segmentation and recognition and understand the basics of the new and improved deep learning module. By the end of this book, you'll be familiar with the basics of Open CV, such as matrix operations, filters, and histograms, and you'll have mastered commonly used computer vision techniques to build OpenCV projects from scratch.
Table of Contents (14 chapters)

Frame differencing

We know that we cannot keep a static background image pattern that can be used to detect objects. One of the ways to fix this would be by using frame differencing. It is one of the simplest techniques we can use to see what parts of the video are moving. When we consider a live video stream, the difference between successive frames gives a lot of information. The concept is fairly straightforward! We just take the difference between successive frames and display the differences between them.

If I move my laptop rapidly, we can see something like this:

Instead of the laptop, let's move the object and see what happens. If I rapidly shake my head, it will look something like this:

As you can see from the previous images, only the moving parts of the video get highlighted. This gives us a good starting point to see what areas are moving in the video....