 Some barcode readers can estimate the translation, orientation, and vertical depth of a known-size barcode relative to the barcode reader.Some sets of fiducial markers are specifically designed to allow rapid, low-latency detection of 6D position estimation (3D location and 3D orientation) and identity of hundreds of unique fiducial markers.For example, the WhyCon marker, WhyCode markers, "amoeba" reacTIVision fiducials, the d-touch fiducials, or the TRIP circular barcode tags (ringcodes).