Book Image

Building Computer Vision Projects with OpenCV 4 and C++

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

Building Computer Vision Projects with OpenCV 4 and C++

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

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. This Learning Path is your guide to understanding OpenCV concepts and algorithms through real-world examples and activities. Through various projects, you'll also discover how to use complex computer vision and machine learning algorithms and face detection to extract the maximum amount of information from images and videos. In later chapters, you'll learn to enhance your videos and images with optical flow analysis and background subtraction. Sections in the Learning Path will help you get to grips with text segmentation and recognition, in addition to guiding you through the basics of the new and improved deep learning modules. By the end of this Learning Path, you will have mastered commonly used computer vision techniques to build OpenCV projects from scratch. This Learning Path includes content from the following Packt books: •Mastering OpenCV 4 - Third Edition by Roy Shilkrot and David Millán Escrivá •Learn OpenCV 4 By Building Projects - Second Edition by David Millán Escrivá, Vinícius G. Mendonça, and Prateek Joshi
Table of Contents (28 chapters)
Title Page
Copyright and Credits
About Packt
Contributors
Preface
Index

Overlaying a face mask 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 our faces. It will look something like this:

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

#include "opencv2/core/utility.hpp"
#include "opencv2/objdetect/objdetect.hpp"
#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"

using namespace cv;
using namespace std;

...

int main(int argc, char* argv[]) 
{ 
    string faceCascadeName = argv[1]; 
     
    // Variable declaration and initialization 
    ...
    // Iterate until the user presses the Esc key 
    while(true) 
    { 
        // Capture the current frame 
        cap >> frame; 
         
        // Resize the frame 
...