Book Image

Qt 5 and OpenCV 4 Computer Vision Projects

By : Zhuo Qingliang
4 (1)
Book Image

Qt 5 and OpenCV 4 Computer Vision Projects

4 (1)
By: Zhuo Qingliang

Overview of this book

OpenCV and Qt have proven to be a winning combination for developing cross-platform computer vision applications. By leveraging their power, you can create robust applications with both an intuitive graphical user interface (GUI) and high-performance capabilities. This book will help you learn through a variety of real-world projects on image processing, face and text recognition, object detection, and high-performance computing. You’ll be able to progressively build on your skills by working on projects of increasing complexity. You’ll begin by creating an image viewer application, building a user interface from scratch by adding menus, performing actions based on key-presses, and applying other functions. As you progress, the book will guide you through using OpenCV image processing and modification functions to edit an image with filters and transformation features. In addition to this, you’ll explore the complex motion analysis and facial landmark detection algorithms, which you can use to build security and face detection applications. Finally, you’ll learn to use pretrained deep learning models in OpenCV and GPUs to filter images quickly. By the end of this book, you will have learned how to effectively develop full-fledged computer vision applications with OpenCV and Qt.
Table of Contents (11 chapters)

Saving videos

In the preceding section, we learned how to access the cameras attached to our computer, as well as getting the information of all the cameras, playing the video that was captured from a camera in real time, and calculating the frame rate of a camera. In this section, we will learn how to record videos from the camera.

The principle of recording videos is simple: while we are capturing frames from a camera, we compress each frame in a certain way and write it to a video file. The VideoWriter class in the videoio module of the OpenCV library provides a convenient way to do this, and we will use it to record videos in this section.

Before we start with the work of recording videos, we should do some preparation work for our application, for example, where to save the video and how to name each video file. To resolve these prerequisites, we will create an assistant...