Augmented reality makes it possible to project virtual 3D visuals in your physical environment or on specific objects. In order to be able to use it as a projection screen, you first have to know what this environment or objects looks like, and what the scale is. If you can only use or want to use the camera of your mobile phone or tablet, you can use markers.
A marker is an image or object whose scale and/or location has been accurately pre-determined. This could be an ordinary user object or a graphic marker created specifically for this purpose. If the object is used specifically for this, we speak of a fiducial marker like for example QR codes. These ‘fiducials’ can also contain coded data.
When the camera gets the marker in view, your mobile phone, tablet or other device can accurately calculate the position (‘pose’) relative to the marker thanks to the known scale and / or position. If that calculation process takes place in real time, we call that tracking. This data can then be used by the device to project AR visual (s) in correct position and proportion.