Glossary Terms

A brain-computer interface (BCI) is a direct communication pathway between the brain and an external device, bypassing conventional physical input. Source: XRSI Standard XR Definitions (XR-001) Read more

Cinematic VR is an immersive video experience in which viewers can look around in all directions but cannot move through or interact with the environment. It is often used for storytelling, walkthroughs, and educational content. Source: Unity Glossary Read more

Classification is a learning problem in which the output is one of a finite set of values, such as a diagnostic category. When only two values are possible it is called binary classification. Source: NIST AI Resource Center Glossary Read more

Computer vision is the field of artificial intelligence that enables software to interpret visual information, recognizing objects, people, and environments. It underpins applications from augmented reality to medical imaging. Source: Unity Glossary Read more

Continual learning is a model’s ability to adapt by incorporating new data or experience over time while retaining prior knowledge. In the medical device context this is termed continuous learning, where the device changes with each exposure to data during operation, raising oversight questions that a locked model does not. Sources: FDA Digital Health and… Read more

A convolutional neural network (CNN) is a specialized deep neural network architecture built around one or more convolution layers. It is suited to grid-like data such as images, which is why it is commonly applied to medical imaging. Source: FDA Digital Health and AI Glossary Read more

Cyber sickness, also called virtual reality sickness, is the discomfort a user feels when they perceive motion in an immersive environment while remaining physically still. Lag, low refresh rates, and visual discrepancies all contribute, and careful content design is needed to reduce it. Source: Unity Glossary Read more

Deep learning is a branch of machine learning that trains neural networks with multiple intermediary, or hidden, layers between the input and the output. The additional layers allow the system to represent more complex relationships in data. Sources: FDA Digital Health and AI Glossary; NIST AI Resource Center Glossary Read more

Degrees of freedom (DoF) describes how an object’s position and orientation in space can change, combining translation along axes with rotation. In XR the term is normally expressed as 3DoF, which tracks rotation only, or 6DoF, which tracks rotation and adds movement through space; a 6DoF device is therefore also capable of 3DoF tracking. Source:… Read more

A digital twin is a virtual model of a physical, real-world asset, such as a device, a system, or a space, that can be used to simulate and analyze the real thing without acting on it directly. Source: XRSI Standard XR Definitions (XR-001) Read more