Difference between revisions of "AR-Marker"

Revision as of 09:08, 19 September 2017

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 and can be used for Direct Augmentation or Device Pose calculation. The AR-Marker ID is defined as an integer value between zero and the maximum dictionary size (see Marker Creation). Once a marker is detected, the ID is used to gather additional information from the associated UBIK® object (see 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 camera of the mobile device has to be calibrated (see Camera Calibration) and the AR-Marker side length has to be known.

Marker Creation

Currently UBIK® is using the standard dictionary, allowing the creation of 1024 unique AR-Marker IDs. Markers can be created using the provided Aruco Marker Creation tool from the release portal (link to Tool). Once the tool is extracted, the ArucoMarkerGenerator.htm can be opened to configure the ID and side length. After clicking Generate Marker, the AR-Marker can be printed.

Note when printing AR-Markers the physical side length has to correlate with the AR-Marker side length property (see Classifications).

Classifications

The most important classification is the SYSCLS_ARMARKER, containting the identi-fier 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 Direct Augmentation and 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. Per default a Billboard, representing the classified UBIK® object, will be shown directly on the AR-Marker. Additional classifications (SYSCLS_ARCONTENTTRANSLATION, SYSCLS_ARCONTENROTATION, SYSCLS_ARCONTENTSCALE) can be used to trans-late, 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 (see AR-Marker Device Pose Estimation)