Glossary Terms

Emotional immersion is immersion driven by narrative rather than by space: the user is absorbed because the content engages them emotionally, without necessarily feeling bodily present in the environment. Source: ACM Metaverse Glossary (Zhang, Perkis & Arndt, 2017) Read more

Explainability is the ability to represent the mechanisms underlying an AI system’s operation, producing a human-interpretable account of why it arrived at a given prediction. Sources: FDA Digital Health and AI Glossary; NIST AI Resource Center Glossary Read more

Extended reality (XR) is the umbrella term for technologies that combine digital content with a person’s perception of the world, covering virtual reality, augmented reality, mixed reality, and immersive technologies still to come. It is best understood as a spectrum: at one end digital content is layered onto the real environment, and at the other… Read more

Eye tracking captures which way a user’s eyes are looking so that software can respond accordingly. It supports gaze-based control and more efficient rendering through foveated rendering. Sources: Unity Glossary; XRSI Standard XR Definitions (XR-001) Read more

Federated learning is a decentralized approach in which each site trains on data kept locally and sends only model updates to a central server. It allows collaboration across institutions without pooling the underlying data. Source: FDA Digital Health and AI Glossary Read more

Field of view (FOV) is the observable area a user can see at once through an XR device while looking straight ahead, usually measured in degrees. A wider field of view fills more of the user’s vision and generally increases the sense of immersion. Sources: Unity Glossary; XRSI Standard XR Definitions (XR-001) Read more

Foundation models are AI models trained on large, typically unlabeled datasets using significant computational resources, which makes them applicable across a wide range of contexts rather than to one narrow task. Source: FDA Digital Health and AI Glossary Read more

Foveated rendering mimics human vision by rendering fine detail only at the centre of the user’s view while reducing quality in the periphery. It improves performance and allows richer visuals on limited hardware. Source: Unity Glossary Read more

Full-body tracking traces the movements of a user’s whole body within an immersive environment, rather than only the head and hands. Source: XRSI Standard XR Definitions (XR-001) Read more

Gaze is the direction, expressed as a ray, in which a user is looking within a virtual scene. It is commonly used as a pointing or selection method in XR interfaces. Source: XRSI Standard XR Definitions (XR-001) Read more