Tutorials Archives - Page 5 of 19

2017-10-212019-05-01

Computer Vision with OpenCV 3 and Qt5, Now Available for Preorder

It is one thing to become an author, but it is totally another level of joy, to be published by my most favorite publisher in the computer science industry. So, it is with great pleasure that today I can announce that my upcoming book about OpenCV and Qt is available for preordering on Amazon, and also from PacktPub. It’s titled “Computer Vision with OpenCV 3 and Qt5”, and it aims to teach both computer vision and application development for developers who are familiar with C++ (on an intermediate level), but want to learn about powerful cross-platform frameworks such as Qt and OpenCV with hands-on examples and clear instructions. The book is in its final stages of completion, so I’m also excited to announce that our goal is to make it available by the beginning of 2018 and we are working hard to make it happen. Here are the links to preorder:

https://www.packtpub.com/application-development/computer-vision-opencv-3-and-qt5

2017-10-162019-06-09

How to Build Qt From Source Codes

In this post you’ll find information about how to build Qt from source. We’ll be building the latest version of Qt, released about a week ago, using its source codes, both dynamically and statically and with various customized configurations. So without further ado, let’s start.

2017-08-132019-05-05

How to Build OpenCV 3.3.X for Android

In this post I’m sharing the required steps for building OpenCV 3.3.X (to be precise, OpenCV 3.3.0 which was released about a week ago) for Android. You can also download the pre-built libraries from here but it’s always a good idea to build the libraries yourself in case you want any special configurations such as Nvidia Carotene, OpenCV World and so on. So here it is:

2017-07-262019-05-01

How to Get Past the Infamous “Insufficient Count of Samples” Error in OpenCV Cascade Training

Many people who have tried OpenCV’s traincascade tool know about a very disturbing error which (at least at the moment) seems to have no good solution, but nevertheless this issue has a solution (even if not convenient) so we need to stick to what we have at hand. My Cascade Trainer GUI app which also uses OpenCV as the underlying framework is also seen to produce this error with many users so I decided to discuss this and share my solution with you all, but please make sure you put your comment below if you’ve got any questions or better suggestions. So, let’s get down to it.

2017-06-012019-05-05

How to Rotate and/or Flip (Mirror) Images in OpenCV

In this post I’m sharing a couple of very simple tricks to perform an efficient Rotate or Flip (Mirror) operation on OpenCV Mat images.

2017-05-242019-06-02

How to Use OpenCV in Unity (Example Project)

This is a post that many people have requested recently. I’m going to describe how you can use OpenCV in Unity. Of course we’ll be using official OpenCV libraries and not any assets or existing plugins. For those of you who aren’t familiar with the subject, Unity is a very popular game engine which allows building games, apps and so called experiences with much ease. Unity allows some modified form of JavaScript and also C# for its scripting. In this example project I’ll use C# since that’s the language I’m familiar with but it shouldn’t be hard to adapt this to JavaScript (but you’re gonna do it yourself if needed, sorry) so let’s start.

2017-03-082019-05-05

OpenCV 3.2.0 Pre-Built Libraries for Android

In this post I’m sharing the pre-built libraries and binaries for OpenCV that I use to build Qt/QML and OpenCV powered apps for Android (armeabi-v7a) phones. An example of such application is Quick-Camera-CV which I shared its source codes in a previous post.

2017-02-102019-05-01

How to Use C++/Qt/QML/OpenCV to Write Mobile Applications

I have avoided using QML for long time and always wrote even the most simple applications using Qt Widgets and C++ code but the release of Qt’s Quick Controls 2 and Material Style just made it very irresistible and I had to go for it. Well it didn’t take too long to get a hold of things (for a newcomer) since I had enough programming experience and QML is just too well-structured and easy to learn and use. In this post I’m going to share a project that demonstrates using OpenCV in QML to write beautiful and powerful Android (and other platforms) apps.

2017-01-092019-05-03

Diffuse Shading in OpenGL Using Qt

This one is taken from one of my favourite books (OpenGL 4.0 Shading Language Cookbook) and the relevant chapter’s title for this tutorial in the book is called “Implementing diffuse, per-vertex shading with a single point light source”. Of course it’s modified to use OpenGL ES in Qt which is more cross-platform and creates less issues with building and running on different operating systems (including Android and iOS)

2017-01-042019-05-03

How to Read Wavefront OBJ Files Using C++/Qt

First of all let’s briefly go through what’s an OBJ File. Here’s a very brief description from Wikipedia: “OBJ (or .OBJ) is a geometry definition file format first developed by Wavefront Technologies for its Advanced Visualizer animation package. The file format is open and has been adopted by other 3D graphics application vendors.” Anyway, I’ll assume that now that since you’re here you already know what an OBJ File is and How and Where to use it.