AR Markers are square fiducial markers composed by a wide black border and a inner binary matrix which determines its identifier (ID). These markers are detected in the camera stream of the [[POI_View|POI View]] and can be used for [[AR-Marker#Direct_Augmentation|Direct Augmentation]] or [[AR-Marker#AR-Marker Device Pose Estimation|Device Pose calculation]].
The AR-Marker ID is defined as an integer value between zero and the maximum dictionary size (see [[AR-Marker#Marker Creation|Marker Creation]]). Once a marker is detected, the ID is used to gather additional information from the associated UBIK® object (see [[AR-Marker#Classifications|Classifications]]).
The four corner points of an AR-Marker are extracted to calculate the relative pose (position and orientation) between the camera and the AR-Marker, which serves as a basement for the above stated use-cases. For that the camera of the mobile device has to be calibrated (see [[Camera_Calibration|Camera Calibration]]) and the AR-Marker side length has to be known.
== Classifications ==
The most important classification is the [[SYSCLS_ARMARKER]], containting the identifier and the AR-Marker side length. Two additional classifications [[SYSCLS_ARMARKER_DIRECTAR ]] and [[SYSCLS_ARMARKER_GEO ]] inherit from the above classiciation and are used to distinguish between the two use-cases of [[AR-Marker#Direct_Augmentation|Direct Augmentation]] and [[AR-Marker#AR-Marker Device Pose Estimation|Device Pose calculation]].
== Direct Augmentation ==
If marked with the [[SYSCLS_ARMARKER_DIRECTAR ]] classification, AR-Markers can be directly augmented once they are detected in the [[POI_View|POI View ]] Per default a Billboard, representing the classified UBIK® object, will be shown directly on the AR-Marker. Additional classifications ([[SYSCLS_ARCONTENTTRANSLATION]], SYSCLS_ARCONTENROTATION[[SYSCLS_ARCONTENTROTATION]], [[SYSCLS_ARCONTENTSCALE]]) can be used to translate, rotate and scale the Billboard in relation to the detected AR-Marker (see AR-Marker Coordinate system). Furthermore it is possible to render multiple UBIK® objects in relation to the same physical AR-Marker.
Depending on the computational capacities of a mobile device, AR-Markers can be directly augmented in realtime (25 Hz).
== AR-Marker Device Pose Estimation ==
If marked with the [[SYSCLS_ARMARKER_GEO ]] classification, AR-Markers can be used for calculating the device pose once they are detected in the [[POI_View|POI View ]] (see AR-Marker Device Pose Estimation)