Book Image

Computer Vision with OpenCV 3 and Qt5

By : Amin Ahmadi Tazehkandi
4 (1)
Book Image

Computer Vision with OpenCV 3 and Qt5

4 (1)
By: Amin Ahmadi Tazehkandi

Overview of this book

Developers have been using OpenCV library to develop computer vision applications for a long time. However, they now need a more effective tool to get the job done and in a much better and modern way. Qt is one of the major frameworks available for this task at the moment. This book will teach you to develop applications with the combination of OpenCV 3 and Qt5, and how to create cross-platform computer vision applications. We’ll begin by introducing Qt, its IDE, and its SDK. Next you’ll learn how to use the OpenCV API to integrate both tools, and see how to configure Qt to use OpenCV. You’ll go on to build a full-fledged computer vision application throughout the book. Later, you’ll create a stunning UI application using the Qt widgets technology, where you’ll display the images after they are processed in an efficient way. At the end of the book, you’ll learn how to convert OpenCV Mat to Qt QImage. You’ll also see how to efficiently process images to filter them, transform them, detect or track objects as well as analyze video. You’ll become better at developing OpenCV applications.
Table of Contents (19 chapters)
Title Page
Dedication
Packt Upsell
Foreword
Contributors
Preface

The Scene, QGraphicsScene


This class provides almost all methods required for multiple graphics items (QGraphicsItem), even though we only used it with a single QGraphicxPixmapItemin the previous example. In this section, we will review some of the most important functions in this class. As it was mentioned before, we'll mainly focus on the properties and methods required for our use case, since covering all methods, although they are all important, would be fruitless for the purpose of our book. We will skip the constructor functions of QGraphicsScene since they are simply used to take the dimensions of the scene and create a scene accordingly. As for the rest of the methods and properties, here they are, and for some of them that may not be too obvious, you can find a simple example code that you can try out with the Graphics_Viewer project we created earlier in this chapter:

  • The addEllipse, addLine, addRect, and addPolygon functions, as it can be guessed from their names, can be used...