In addition to handheld video see-through and wearable optical see-through, there are other AR display techniques as well.
A monocular headset shows a single image in one eye, allowing the other eye to view the real world unaugmented. It tends to be lightweight and used more as a heads-up display (HUD), as if information were projected on the front of a helmet rather than registered to the 3D world. An example of this is Google Glass. While the technology can be useful in some applications, we are not considering it in this book.
Wearable video see-through uses a head-mounted display (HMD) with a camera and combines real-world video with virtual graphics on its near-eye display. This may be possible on VR headsets ...
