ArUco Marker

A square fiducial marker composed of a black border and an inner binary pattern that encodes a unique ID, designed for fast, robust pose estimation from a single camera image. ArUco markers are widely supported by OpenCV and are used in augmented reality, robotics, and research prototypes — including accessibility wearables — to mark objects or locations whose 3D position and orientation must be recovered in real time. They are typically a stand-in used in lab demonstrations until markerless object recognition becomes reliable enough to replace them.