Tracking methods in augmented reality: precise placement of virtual content in space
Augmented reality (AR) is a fascinating technology that seamlessly integrates virtual content with the real world. One of the critical components that enables this seamless integration is tracking. Various types of tracking are used to determine the exact position and orientation of AR content in the environment. Here are some of the common tracking methods in AR:
World Space Tracking
World Space Tracking also called camera position estimation or position tracking, refers to the process of accurately determining the position and orientation of a device (such as a smartphone or AR headset) in relation to the physical environment. This includes tracking the movement and rotation of the device in three-dimensional space. The main goal of world space tracking is to precisely align virtual content with the real world to ensure that virtual objects appear anchored and stable in the user's field of view. However, world space tracking often results in virtual elements that should be placed on a surface appearing to float. World space tracking works best for elements that are intended to float in space. To fix objects to a wall or floor, it is better to use plane detection.
Areas of application:
Gaming: Enables accurate positioning of virtual characters or objects in the real environment to create an immersive gaming experience.
Architecture and Design: Supports the visualization and planning of buildings by allowing virtual models to be integrated into real space.
E-commerce: Allows virtual trying on of clothes or placing virtual furniture in one's own rooms to facilitate purchasing decisions.
Spatial Perception
Spatial Perception is a comprehensive approach that includes various technologies and algorithms. It allows AR devices to perceive and understand the physical environment. Cameras, depth sensors and lidar are used so that information about the environment can be captured, such as surface details, dimensions of objects and spatial structure. This enables realistic integration of AR content into the physical environment.
Areas of application:
Education and training: Enables interactive learning environments where virtual content can be combined with real-world objects to enhance learning processes.
Navigation and orientation: Provides visual guidance or augmented reality maps to help users navigate unfamiliar environments.
Art and creativity: Enables the creation of immersive artworks or interactive installations that integrate virtual elements into the physical environment.
Marker Tracking or Image Tracking
Marker tracking is based on the use of special markers or QR codes that are recognized by the AR application. These markers serve as reference points to precisely place AR content in the real world. It provides high accuracy and stability because the markers represent a unique visual feature that can be easily tracked. The image can be a photo, a logo, or any recognizable 2D object that can be detected by the camera. The disadvantage of marker tracking is that it does not work without the marker. So you always have to have a marker in digital or printed form for your audience to use the AR application.
Areas of application:
Advertising and marketing: use special markers in print media or posters to offer interactive AR experiences and increase audience engagement.
Industrial applications: Assists in the assembly or maintenance of machinery by placing AR content on special markers to provide instructions or information.
Medical Simulation: Allows virtual models or visualizations to be placed on specific markers to perform medical training or simulation.
Not every image is suitable as an image marker for AR tracking
This is what you should consider when choosing a marker
When selecting images as markers for AR image tracking, clear contrasts and distinct features are important. Simple shapes such as squares or circles work well, as do saturated colors for better recognition. The marker should be clearly distinguishable from other objects and remain robustly recognizable in a variety of conditions. Artificially added details can also improve recognition. Consider the application context to choose an appropriate marker, such as QR codes or special logos. Test different markers to ensure a reliable AR experience.
Plane Detection
Another important tracking method is Plane Detection. Instead of a traditional 2D image, some AR applications can also detect surfaces and use them instead of an image. This is an advantage if you want to let the user decide where they want to place the content, or if you want to work with large models where scale and model size accuracy are important. This technology detects horizontal or vertical surfaces in the real world, such as floors, tables, walls or ceilings. By using computer vision algorithms, characteristic patterns or structures are identified that indicate flat surfaces. AR content can be precisely placed on these detected surfaces, creating a seamless integration of virtual and real elements.
This video shows Plain Detection on the left and World Space Detection on the right. World Space Detection makes the virtual object "float".
Areas of application:
Furnishing and Decorating: Assists in the virtual placement of furniture, artwork or decorative items so that the appearance of a room can be visualized prior to purchase or remodeling.
Augmented Reality Gaming: Provides an interactive gaming environment where virtual objects can be placed on real surfaces to create exciting and entertaining gaming experiences.
Architecture and construction: Enables architects and builders to project virtual models of buildings into real space to review designs or visualize construction progress.
Plane detection is a tracking technology that is mainly used in apps programmed with ARCore or ARKit. In the WebAR area, plane detection is not supported by most frameworks. Here, world space tracking is usually used as a substitute.
GPS tracking
GPS tracking uses the Global Positioning System (GPS) to determine the geographic position of the AR device. It enables AR applications to display location-based content, such as information about places of interest, navigation instructions, or location-based games. GPS tracking can be particularly useful outdoors, where broad GPS signal coverage is available. The most prominent example of GPS tracking is Pokemon GO. GPS tracking is not particularly precise. Therefore, GPS tracking is often combined with other tracking methods.
Areas of application:
Location-based information: Displays information about nearby attractions, restaurants or stores based on the user's location.
Tourist Applications: Provides guided tours or information on historical sites based on the user's current location.
Fitness and outdoor activities: Tracks and analyzes activities such as jogging or cycling to record distance, speed and route.
SLAM tracking
Finally, SLAM (Simultaneous Localization and Mapping) tracking is an advanced method that combines camera technology, sensors and special algorithms. SLAM detects the position and orientation of the AR device in real time and simultaneously creates a map of the environment. This is done by tracking detected features and structures. SLAM enables precise positioning of virtual objects in the real world. Slam tracking is arguably the most precise tracking method for placing virtual objects in space. Slam is also a tracking method that is extremely rare in WebAR and is supported by app development frameworks such as Vuforia and Wikitude. The Hololens 2 also supports slam to create a spatial model of the environment.
Areas of application:
Robotics and autonomous systems: Supports robots or autonomous vehicles in the spatial localization and mapping of their environment.
Industrial inspection and maintenance: Enables the overlay of AR data on real objects to support inspection and maintenance processes.
Military and Defense: Can be used to support tactical operations or to create virtual models of battlefields.
The variety of tracking methods in augmented reality enables precise placement of virtual content. Thus, these technologies provide a more immersive and interactive AR experience From accurate positioning on surfaces to capturing the user's movements . With continued advancements in AR technology, we are sure to see more impressive tracking methods in the future that will continue to expand the potential of AR.