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

Drawing in OpenCV


It's impossible to ignore drawing text and shapes on an image when the subject is OpenCV and computer vision in general. For countless reasons, you will need to draw (output) some text or shapes on the output images. For example, you may want to write a program that prints the date of the image (or images) on it. Or you may want to draw a square around faces in the after performing a face detection. Even though Qt framework also provides quite powerful functions to deal with such tasks, it is also possible to use OpenCV itself to draw on images. In this section, you will learn about using OpenCV drawing functions one by one, which are surprisingly very easy to use, along with example codes and output results.

Drawing functions in OpenCV accept an input and output image, quite understandably, along with a few parameters which are common to most of them. Here are the mentioned common parameters of drawing functions in OpenCV along with their meaning and possible values:

  • color...