How do Augmented Reality Glasses work?
How do augmented reality glasses work? This question is almost unavoidable for many who deal with Augmented Reality. To understand how augmented reality glasses work, you first have to understand how AR works / what AR is.
How does Augmented Reality work?
Augmented Reality integrates virtual objects such as text, images or videos into the real world to expand it. The user still perceives his real environment. On the other hand, virtual reality, overlays the user’s field of vision completely overlaid with a digital environment. You can find a more detailed explanation in our article “What is Augmented Reality? A (new) definition”
Functionality of Head Mounted Displays
One way to bring these virtual objects into the user’s field of view is to use head-mounted displays. These are screens that are attached directly to the user’s head. This is how not only augmented reality glasses, but also virtual reality glasses work.
Augmented reality glasses, like the Microsoft HoloLens, are therefore basically a see-through display that is attached to the user’s head. A distinction can be made between optical and video see-through displays.
- Optical See-Through: A transparent display that also acts as a projection screen, allowing the user to perceive the real world directly and to receive additional digital information. Another possibility for optical see-through is the projection of digital objects by a laser into the eye of the user.
- Video See-Through: With Video See-Through the user cannot look through the display. Instead, a camera records the image of the outside world. This image is then placed on the projection surface and supplemented by digital elements. Mobile phones and tablets and some digital cameras fall into this category.
In order to be able to perceive the surroundings, numerous sensors such as depth cameras or time-of-flight cameras are located in the front of the glasses.
Time-of-flight camera
A time-of-flight camera helps to capture the depth of the room. To do this, the camera sends out invisible light pulses. Objects in the room towards which the camera is pointed reflect this light and the time-of-flight sensor registers how long it takes for the light pulses to return to the camera. The longer the determined time for one pixel, the further away ist he object. Because oft hat the augmented reality glasses can capture reality even in not so good lighting conditions which is called mapping.
The Augmented Reality Glasses “HoloLens” by Microsoft
Control of Augmented Reality glasses
With these cameras and sensors, augmented reality glasses can see the environment in three dimensions similar to the human eye. This enables the glasses to place digital objects correctly in the real world. Furthermore technologies such as Infineon radar technology can support the cameras to detect the environment.
There are various possibilities for controlling augmented reality glasses. In the case of the Microsoft HoloLens, the user controls the device by moving his head or field of vision and by gesture control. The Google Glass can be controlled by a touch screen on the side of the device as well as by eye tracking and blinking of the user. The user can also control other Smart Glasses for example through a controller or smartphone.
How do Augmented Reality glasses work? Conclusion
Augmented reality glasses are see-through displays that are worn by the user like glasses. The environment is scanned by different cameras in the AR-glasses in order to
Image source: https://commons.wikimedia.org/wiki/File:Ramahololens.jpg (edited)
Literature: https://www.springer.com/de/book/9783642141782
