Book Image

OpenCV By Example

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

OpenCV By Example

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

Overview of this book

Open CV is a cross-platform, free-for-use library that is primarily used for real-time Computer Vision and image processing. It is considered to be one of the best open source libraries that helps developers focus on constructing complete projects on image processing, motion detection, and image segmentation. Whether you are completely new to the concept of Computer Vision or have a basic understanding of it, this book will be your guide to understanding the basic OpenCV concepts and algorithms through amazing real-world examples and projects. Starting from the installation of OpenCV on your system and understanding the basics of image processing, we swiftly move on to creating optical flow video analysis or text recognition in complex scenes, and will take you through the commonly used Computer Vision techniques to build your own Open CV projects from scratch. By the end of this book, you will be familiar with the basics of Open CV such as matrix operations, filters, and histograms, as well as more advanced concepts such as segmentation, machine learning, complex video analysis, and text recognition.
Table of Contents (18 chapters)
OpenCV By Example
Credits
About the Authors
About the Reviewers
www.PacktPub.com
Preface
Index

Overlaying a facemask in a live video


OpenCV provides a nice face detection framework. We just need to load the cascade file and use it to detect the faces in an image. When we capture a video stream from the webcam, we can overlay funny masks on top of our faces. It will look something like this:

Let's take a look at the main parts of the code to see how to overlay the preceding mask on top of the face in the input video stream. The complete code is available in the downloadable code bundle provided along with this book:

int main(int argc, char* argv[])
{
    string faceCascadeName = argv[1];
    
    // Variable declarations and initializations
    
    // Iterate until the user presses the Esc key
    while(true)
    {
        // Capture the current frame
        cap >> frame;
        
        // Resize the frame
        resize(frame, frame, Size(), scalingFactor, scalingFactor, INTER_AREA);
        
        // Convert to grayscale
        cvtColor(frame, frameGray, CV_BGR2GRAY);...