In order to achieve the overall outcome of this book, the following are the prerequisites:

• You need to have some basic knowledge of C++ and C programming languages.
• You need to have Qt v5.0 or above installed.
• You need to have a webcam attached to your computer.
• Many libraries, such as OpenCV and Tesseract, are also required. The instructions to install them are included in the chapter in which each library is first used.
• A knowledge of deep learning and heterogeneous computing will be an advantage in helping to understand some chapters.

You can download the example code files for this book from your account at www.packt.com. If you purchased this book elsewhere, you can visit www.packt.com/support and register to have the files emailed directly to you.

You can download the code files by following these steps:

1. Log in or register at www.packt.com.
2. Select the SUPPORT tab.
3. Click on Code Downloads & Errata.
4. Enter the name of the book in the Search box and follow the onscreen instructions.

Once the file is downloaded, please make sure that you unzip or extract the folder using the latest version of:

• WinRAR/7-Zip for Windows
• Zipeg/iZip/UnRarX for Mac
• 7-Zip/PeaZip for Linux

The code bundle for the book is also hosted on GitHub at https://github.com/PacktPublishing/Qt-5-and-OpenCV-4-Computer-Vision-Projects. In case there's an update to the code, it will be updated on the existing GitHub repository.

We also have other code bundles from our rich catalog of books and videos available at https://github.com/PacktPublishing/. Check them out!

We also provide a PDF file that has color images of the screenshots/diagrams used in this book. You can download it here: http://www.packtpub.com/sites/default/files/downloads/9781789532586_ColorImages.pdf.

Visit the following link to check out videos of the code being run: http://bit.ly/2FfYSDS.

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, class or type names. Here is an example: "The Qt project file, ImageViewer.pro, should be renamed ImageEditor.pro. You can do this in your file manager or in a Terminal."

A block of code is set as follows:

         QMenu *editMenu;
         QToolBar *editToolBar;
         QAction *blurAction;

When we wish to draw your attention to a particular part of a code block, a comment will be appended to end of the lines:

         // for editting
         void blurImage();

Any command-line input or output is written as follows:

    $ mkdir Chapter-02
    $ cp -r Chapter-01/ImageViewer/ Chapter-02/ImageEditor
    $ ls Chapter-02
    ImageEditor
    $ cd Chapter-02/ImageEditor
    $ make clean
    $ rm -f ImageViewer

The $ symbol is the shell prompt, and the text after it is a command. The lines that don't start with a $ are the output of the preceding command.