Mixed reality is the result of blending the physical world with the digital world. Mixed reality is the next evolution in human, computer, and environment interaction and unlocks possibilities that before now were restricted to our imaginations. It is made possible by advancements in computer vision, graphical processing power, display technology, and input systems. The term mixed reality was originally introduced in a 1994 paper by Paul Milgram and Fumio Kishino, "A Taxonomy of Mixed Reality Visual Displays." Their paper introduced the concept of the virtuality continuum and focused on how the categorization of taxonomy applied to displays. Since then, the application of mixed reality goes beyond displays but also includes environmental input, spatial sound, and location.
Advancements in sensors and processing are giving rise to a new area of computer input from environments. The interaction between computers and environments is effectively environmental understanding, or perception. Hence the API names in Windows that reveal environmental information are called the perception APIs. Environmental input captures things like a person's position in the world (e.g. head tracking), surfaces and boundaries (e.g. spatial mapping and spatial understanding), ambient lighting, environmental sound, object recognition, and location.
Now, the combination of all three – computer processing, human input, and environmental input – sets the opportunity to create true mixed reality experiences. Movement through the physical world can translate to movement in the digital world. Boundaries in the physical world can influence application experiences, such as game play, in the digital world. Without environmental input, experiences cannot blend between the physical and digital realities.
Since mixed reality is the blending of the physical world and digital world, these two realities define the polar ends of a spectrum known as the virtuality continuum. For simplicity, we refer to this as the mixed reality spectrum. On the left-hand side we have physical reality in which we, humans, exist. Then on the right-hand side we have the corresponding digital reality.
Most mobile phones on the market today have little to no environmental understanding capabilities. Thus the experiences they offer cannot mix between physical and digital realities. The experiences that overlay graphics on video streams of the physical world are augmented reality, and the experiences that occlude your view to present a digital experience are virtual reality. As you can see, the experiences enabled between these two extremes is mixed reality:
Most augmented reality and virtual reality offerings available today represent a very small part of this spectrum. They are, however, subsets of the larger mixed reality spectrum. Windows 10 is built with the entire spectrum in mind, and allows blending digital representations of people, places and things with the real world.
There are two main types of devices that deliver Windows Mixed Reality experiences:
|Characteristic||Holographic Devices||Immersive Devices|
|Example Device|| Microsoft HoloLens|| Acer Windows Mixed Reality Development Edition
|Display||See-through display. Allows user to see physical environment while wearing the headset.||Opaque display. Blocks out the physical environment while wearing the headset.|
|Movement||Full six-degrees-of-freedom movement, both rotation and translation.||Full six-degrees-of-freedom movement, both rotation and translation.|
Note, whether a device is connected to or tethered to a separate PC (via USB cable or Wi-Fi) or self-contained (untethered) does not reflect whether a device is holographic or immersive. Certainly, features that improve mobility lead to better experiences and both holographic and immersive devices could be tethered or untethered.
Technological advancement is what has enabled mixed reality experiences. There are no devices today that can run experiences across the entire spectrum; however, Windows 10 provides a common mixed reality platform for both device manufacturers and developers. Devices today can support a specific range within the mixed reality spectrum, and over time new devices should expand that range. In the future, holographic devices will become more immersive, and immersive devices will become more holographic.
Often, it is best to think what type of experience an app or game developer wants to create. The experiences will typically target a specific point or part on the spectrum. Then, developers should consider the capabilities of devices they want to target. For example, experiences that rely on the physical world will run best on HoloLens.
Here's how different experiences take advantage of their position on the mixed reality spectrum:
Skype for HoloLens, Fragments and RoboRaid are best experienced with HoloLens. Likewise, 360° video is best experienced on immersive devices. HoloTour showcases the best of what both types of devices can do today when trying to push towards the center experience of mixed reality.