Markers are recognized by the camera to determine the position and orientation of virtual objects. Examples are QR codes, special symbols or real objects.
Different types of markers
There are different types of markers that are used depending on the application and technology. Visual markers such as QR codes or special symbols are often used in AR applications, while in MR, real objects can also serve as markers.
There are also markerless systems where no physical markers are needed because the environment itself serves as a reference.
Marker-based interactions
Markers can not only indicate static objects, but also control interactive content. For example, by scanning a marker, a user can explore 3D objects, start animations, or even experience complex data visualizations in real time. See also Marker-based AR.
Challenges and Future of Markers in XR
Although markers are indispensable in many applications, there are technical challenges, such as recognition under difficult lighting conditions or in complex environments.
With advances in computer vision, the use of markers may be replaced in the future by markerless approaches that are even more flexible and user-friendly.
Facts and Features
- Tracking technology: Markers are detected by XR systems using cameras and computer vision algorithms to place virtual objects in the correct location.
- Multiple marker sizes: Markers can be used in various sizes, with larger markers often providing greater detection accuracy.
- Different materials: Markers can be printed or projected on materials, including paper, glass, and even clothing.
- Combination with GPS: In some AR applications, markers are combined with GPS data to enable accurate outdoor positioning.
- Dynamic markers: There are markers that can change or adapt, for example using LEDs or screens to display different content.
- Image-based markers: In addition to symbolic markers, images, logos, or artwork can be used as visual markers for XR applications.
- Data storage in markers: Some markers, such as QR codes, can contain additional information that is integrated directly into the AR experience, such as URLs or metadata.
- User-centric interaction: Markers can be used to control user actions in AR experiences, such as pointing to a specific marker to trigger an event.
Frequently Asked Questions
What technologies are used to detect tags?
Markers are typically detected using cameras and computer vision algorithms that analyze their position and orientation to accurately place virtual content.
Can markers be invisible?
Yes, there are invisible markers that operate in the infrared spectrum. These are invisible to the human eye, but can be detected by special cameras or sensors.
Where are markers used outside of XR?
Markers are also used in logistics, retail, and industrial manufacturing to identify and track objects and support automation processes.
How does the environment affect marker detection?
Lighting conditions, shadows or reflective surfaces can make it difficult to detect markers, so well-lit and high-contrast environments are preferred.
Are there alternatives to physical tags?
Yes, there are markerless technologies that do not require physical markers. These use the natural environment or special algorithms to place virtual objects.
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