The modern world does not cease to delight us with the achievements of technology, who, if not habrazhiteli, knows this. I still carry all sorts of virtual reality helmets to something more sci-fi than real, despite the fact that they already exist (it is enough to search for the Oculus Rift ). In addition, if I may say so, to “pure” virtual reality, projects to supplement our reality (Augmented Reality) seem to be more and more interesting. The castAR project on Kickstarter is a living proof of this, and Google Glass, although not quite that, but fits perfectly into the term augmentation.

BUT alone, Oculus Rift - for today it is a version for developers, castAR - in general only a concept, well, Google Glass only got the lucky ones and its capabilities are severely limited. In general, we cannot talk about reaching a wide audience. But all sorts of smartphones have settled in our lives everywhere. They are all wonderful, have a camera and are smart enough to become the window into augmented reality.

In this article I will talk about Vuforia - a framework that allows you to do something similar with your phone. The post is rather a review to understand the terminology and understand how all this is done.

Vuforia is a platform for creating augmented reality apps for phones and tablets on iOS and Android operating systems. I must say, I was pleasantly surprised that Qualcomm, in addition to producing the iron component of our favorite gadgets, also provides such tools for developers.
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The core of the platform is the QCAR library, written in C ++ and hiding almost everything from its definition of a target (target) behind its interfaces and ending with the rendering of a picture.

In addition to the library, the platform includes: iOS and Android Vuforia SDK for developers; Target Manager - a system for creating and managing targets; as well as a set of web services ( Vuforia Web Services ) in which you can take storage of targets and some other functionality. The platform develops very dynamically and new parts are added quite often.

I have already mentioned target or target several times, so there is nothing left but to tell about it in more detail.

Targets

To add something to the real world, you need to “cling” to an object in this world. It is for this purpose that they serve as targets. In other words, a target is a real object, knowing that our application can place virtual objects in the right places and appropriate proportions.

Vuforia provides a rich selection of targets:

• Image targets - a basic view of targets, which is a regular picture, for example, a magazine cover, a photo or a poster for a new film. The picture plays the role of a kind of two-dimensional bar code, only without black and white regions. According to it, we can determine exactly which picture got into the camera lens, as well as its location in space and scale. It is worth saying that not every picture is suitable for creating a target. Good targets are those in which there are many contrasting details. It is on these details that the reference matrix is ​​built for the subsequent recognition of targets.
• Simple 3D targets (Cube and Cuboid) are targets in the form of rectangular parallelepipeds (including a cube). For example, such a target could be a breakfast cereal package, a matchbox, or a board game that was just bought. Like any box, such a target consists of six planes, and to create it, we need six pictures for each of them. If you ever glued a cube of paper - then quickly cope with the task.
• Cylinder targets - this type of targets, despite the name, is a truncated cone with the ability to set the diameters of the bases. Of course, if you choose the same diameters, then you get just a cylinder, but still this is a special case. In order to create such a target, we need not only to indicate the diameters of the bases and the height, but also to add three pictures - one for each of the two bases, and one more for the side surface.
• Frame markers - this target in the form of a specially prepared frame, which is already much more like a barcode. In this frame you can put any picture. This type of targets is great in case the picture was not detailed enough and it was impossible to create an intelligent image target out of it.
• Text (word targets) . The Vuforia library also has text recognition, so any word or combination of them can be a target. At the moment, only Latin is supported, but this is already very interesting. Just imagine how interesting the study of foreign words can be.

Depending on the number of targets required for your application, you can either store them in the so-called Device Database , always have access to them and recognize them directly on the device itself, or shift some of this load to Cloud Databases - a service from the Vuforia Web Services set designed to store targets and determine them based on the data sent from the device. Both approaches have their pros and cons, but choosing the goals of your application will not be so difficult to choose.

In addition, targets can be created directly from the application itself using the image obtained from the camera.

It is also worth noting that QCAR does not require hitting the entire target in the frame. In order to recognize and use it, only a part will be enough. This is very important and allows you to view all the magic of your application from various angles.

Magic

It’s harder to come up with a more beaten phrase than “Give me a foothold and I will turn the Earth!”, But here it fits perfectly. Now, having the opportunity to “catch on”, we can begin to add the very magic that can be seen on the smartphone screen in our real world.

To do this, let's see what kind of magic we can afford. For this, I tried to collect basic examples of using augmented reality and all of them can be used with Vuforia.

• Static and dynamic 3D models . We can add any 3D object starting from the favorite of all the teapots and ending with complex animation. Vuforia actively supports the ability to integrate with Unity, which even more unties our hands. We are limited only by the imagination and power of smartphones / tablets.
• Virtual buttons to interact with which will have quite a real objects. For example, it could be a button on your target, clicking on which launches a virtual ground-to-air rocket from your desktop can be viewed only through the screen of a smartphone.
• Videos and pictures that allow you to replace our target or make it a little bit more alive.
• Changing the background , among other things, you can change the picture itself received from the camera. In other words, we can not only complement the picture, but also operate with it.

Having such an impressive set of tools you can do almost anything.

As I said, this article is more likely a review, and its purpose was to introduce you to Vuforia and give food for imagination. If the topic finds a response in the hearts of habolic, then in the next article I will consider the examples provided by Vuforia along with the Android SDK, I will describe the code that is there, or maybe we will quickly do something. And lastly, the video that personally blew my head off and made me jump like a little boy who first saw the capital.

useful links

• Project website
• Qualcomm page
• Developers portal
• Vuforia API
• Vuforia SDK with examples