Glossary

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Micro-Navigation(also: Micro Navigation)

The process of navigating the immediate environment — detecting and avoiding obstacles, following the edge of a pavement, identifying surface changes, and maintaining a safe path. For blind and visually impaired travellers, micro-navigation is the domain of traditional primary…

Mirror Neuron System(also: Mirror Neurons)

The mirror neuron system is a network of brain regions that activate both when a person performs an action and when they observe another person performing the same action. It is implicated in motor simulation, action understanding, and learning by imitation. Neuroscientific…

Mixed-Visual Group(also: Mixed visual ability group, Mixed-visual ability group)

A group whose members include both blind or low-vision and sighted participants. The term is used in accessibility research on group activities (museum tours, classrooms, family outings, workplace meetings) to focus on the specific accessibility challenges that arise when blind…

Music Notation(also: Musical Notation, Sheet Music)

A system of written symbols used to represent musical sounds, including pitch, rhythm, dynamics, and other performance instructions. Standard visual music notation uses staff lines, notes, and other graphical symbols that are inherently visual. For blind and visually impaired…

NavCog(also: Navigational Cognitive Assistant)

A Bluetooth beacon-based navigation system developed at Carnegie Mellon University that provides indoor turn-by-turn navigation assistance and environmental information to blind and visually impaired users via smartphone. NavCog works by detecting BLE (Bluetooth Low Energy)…

NavTap

A navigational text-entry method designed for blind mobile phone users that reduces the cognitive load associated with inputting text without visual feedback. NavTap organizes the alphabet into five rows beginning with vowels and allows users to navigate between letters using…

Non-Visual Drawing(also: Blind Drawing, Drawing Without Sight)

The practice of creating graphical representations — such as diagrams, shapes, charts, or illustrations — without relying on visual feedback. Non-visual drawing can be accomplished through tactile methods (using raised line drawing kits or embossing tools), audio-tactile methods…

Non-Visual Exploration(also: Non-Visual Interaction, Non-Visual Scanning)

The process by which blind or visually impaired people gather information about their physical environment, documents, or interfaces without relying on sight. Non-visual exploration combines multiple strategies including touch, audio feedback, spatial memory, contextual…

Non-Visual Interaction(also: Non-Visual Access, Non-Visual Interface)

Methods of interacting with computer systems and digital content without relying on visual display. Non-visual interaction encompasses screen reader output, speech interfaces, keyboard navigation with audio feedback, braille displays, and haptic feedback. The Raman Principle…

Nonvisual Accessibility(also: Non-Visual Access)

Nonvisual accessibility refers to approaches, strategies, and technologies that enable people who are blind or have low vision to access information and interact with digital and physical environments without relying on sight. This encompasses screen readers, braille displays,…

Nonvisual Interaction(also: Eyes-Free Interaction, Screenless Interaction)

Interaction with computing devices without relying on visual feedback, using alternative channels such as audio, tactile, or proprioceptive cues. Nonvisual interaction is essential for blind and low-vision users but also benefits sighted users in eyes-busy contexts like driving…

ORBIT Dataset(also: Object Recognition for Blind Image Training)

A disability-first machine learning dataset for teachable object recognition, contributed by people who are blind or have low vision. The original ORBIT dataset (Massiceti et al., 2021) contains 3,822 videos of 486 objects from 67 data collectors, predominantly in the UK and…

Omakase(also: Omakase mode, I leave it to you)

A Japanese word — literally 'I leave it to you' — adopted in human-robot interaction and assistive-AI research to describe a mode of user involvement in which the person defers all decisions to the system. In autonomous navigation robots for blind travellers, omakase denotes the…

Online Braille(also: Web Braille, Digital Braille, Electronic Braille)

Online Braille refers to Braille content that is generated, distributed, or accessed through the Internet or digital platforms, as opposed to traditional embossed paper Braille. This includes web-based Braille translation services, downloadable Braille-formatted files such as…

Opticon(also: Optical-to-Tactile Converter)

An early assistive technology device developed by Dr. James Bliss in the 1960s that converts printed text into a tactile vibrating pattern that can be read with the fingertip. The Opticon uses a small camera to scan printed characters and reproduces them as patterns of vibrating…

PVI(also: People with Visual Impairments, Person with Visual Impairment, Persons with Visual Impairments)

An abbreviation widely used in HCI and accessibility research for "people with visual impairments," a person-first umbrella term that includes people who are blind, legally blind, or have low vision. PVI is often used interchangeably with BVI ("blind and visually impaired") and…

Page Fragmentation(also: Visual Fragmentation, Content Fragmentation)

A web accessibility problem where different types of content on a web page (news articles, advertisements, navigation menus, related links) are visually grouped using colours, spacing, images, and layout but lack structural markup that would allow non-visual users to identify…

Palm Drawing(also: Palm Mapping, Palm Tracing)

A technique used by Orientation and Mobility (O&M) specialists to teach routes to people who are blind or have low vision. The instructor holds the person's palm face up and traces the path of a route with their finger while simultaneously providing verbal instructions. This…

Parents with Visual Impairments(also: PVI, Blind Parents, Visually Impaired Parents)

Parents with visual impairments (PVI) are blind or low-vision adults raising children, who are often sighted. PVI face distinctive parenting challenges that go beyond individual functional compensation: supporting children's visually-driven exploration (pointing, gaze, shared…

Peripersonal Space(also: Near space, Reaching space)

The area immediately surrounding the body that is within arm's reach, typically extending about 60-70 cm from the body. Peripersonal space is significant in accessibility because blind and visually impaired children often have delayed development of spatial awareness within this…

Personal Safety Management(also: PSM)

Personal Safety Management refers to the informed, agential, and proactive participation of an individual in maintaining their own physical safety. Coined in accessibility research by Branham et al. (2017), the concept highlights how people with disabilities — particularly those…

Personalized Object Recognition(also: Teachable Object Recognition)

A class of computer vision systems that allow an individual user — typically someone who is blind or has low vision — to train their device to recognize a small set of personally relevant objects (a specific coffee mug, a particular set of keys, a favourite notebook) by…

Photo Sharing(also: Photograph Sharing, Image Sharing)

The activity of showing, distributing, or discussing photographs with others — in person, via email, or through social-networking platforms. As a social practice it conveys memories, experiences, and identity; as an accessibility concern it presents barriers for blind and…

RGBD Camera(also: RGB-D Camera, Depth Camera, Stereo Camera)

A camera that captures both a colour (RGB) image and a per-pixel depth (D) measurement of the scene, yielding a 3D representation of the environment. Depth can be produced by stereo vision, structured light, or time-of-flight sensing. In accessibility research RGBD cameras…

Raised-Line Drawing(also: Raised-Line Picture, Tactile Line Drawing, Embossed Line Drawing)

A raised-line drawing is a tactile representation of a visual image created by producing elevated lines on a surface that can be felt by touch, enabling blind and visually impaired people to perceive graphical information through their fingertips. Raised-line drawings can be…

Reading Assistant(also: Reading Aid, Reading Machine)

An assistive technology device or software application that helps people with visual impairments or reading disabilities access printed or displayed text. Reading assistants may use optical character recognition to convert text images to speech, magnification to enlarge text, or…

Refreshable Braille Display(also: Refreshable Braille, Dynamic Braille Display, Electronic Braille Display)

An electromechanical device that renders Braille characters by raising and lowering pins dynamically, allowing blind users to read digital text through touch. Conventional refreshable Braille displays present a single line of text (typically 20-80 characters) using piezoelectric…

Risk-Free Exploration(also: Safe Exploration)

Risk-free exploration is a design principle for making touchscreen interfaces accessible to blind users by enabling them to explore the screen surface without accidentally triggering interface actions. On standard capacitive touchscreens, any finger contact can activate buttons,…

Route Learning(also: Route Familiarization)

The process by which a traveler — particularly a blind or low-vision person — acquires a mental representation of a specific path through an environment, including its turns, landmarks, distances, surface changes, and points of interest. Route learning is a core component of…

Route Planning(also: Journey Planning, Pre-Journey Planning)

The process of determining a path from an origin to a destination before travel begins, including selecting roads or paths, identifying landmarks and decision points, and considering factors such as safety, accessibility, and personal preferences. For blind and visually impaired…

Scanning Navigation(also: Non-Visual Scanning, Auditory Scanning)

A non-visual navigation strategy in which a screen-reader or voice-browser user steps rapidly through a page one fragment at a time — line by line, item by item, or in fixed jumps (e.g. page-down keys) — listening just long enough to each fragment to detect an 'information…

Sensory Compensation(also: Cross-Modal Plasticity, Sensory Substitution)

The phenomenon whereby the loss of one sense leads to enhanced abilities in remaining senses, driven by neuro-plasticity — the brain's capacity to reorganise its neural pathways. Research shows that blind individuals, particularly those blind from birth or early childhood,…

Social Interaction(also: Social Communication, Interpersonal Interaction)

The process by which people act and react in relation to one another, including verbal conversation, non-verbal communication, and physical proximity. For people with disabilities, social interactions can be significantly affected — for example, individuals who are blind may…

Sound Localization(also: Auditory Localization)

The ability to determine the direction and distance of a sound source using auditory cues such as differences in timing and intensity between the two ears. Blind and visually impaired people often develop enhanced sound localization skills as a compensatory strategy for…

Spatial Audio(also: 3D Audio, Spatialised Sound, Binaural Audio)

Audio technology that creates the perception of sound coming from specific locations in three-dimensional space around the listener, using techniques such as head-related transfer functions (HRTFs), binaural rendering, and ambisonics. In accessibility, spatial audio can convey…

Spatialized Sound(also: Spatial Audio, 3D Audio, Spatialized Audio)

Audio that is rendered with positional information so that it appears to originate from a specific location in three-dimensional space around the listener. Spatialized sound uses techniques like head-related transfer functions (HRTFs), interaural time differences, and interaural…

Stereo Vision(also: Stereoscopic Vision, Stereo Camera System, Stereopsis)

A computer vision technique that uses two or more cameras positioned at slightly different viewpoints to extract three-dimensional depth information from a scene, mimicking the way human binocular vision perceives depth. In assistive technology, stereo vision systems have been…

Suitcase Robot(also: Suitcase-shaped robot, Robotic suitcase)

A class of autonomous navigation robots housed inside a rolling suitcase or carry-on-shaped enclosure, designed so that a blind or low-vision user can grip the handle and be guided to a destination while appearing to any onlooker to simply be walking with a piece of luggage. The…

Tactile Dowsing

An interaction technique that uses vibrotactile feedback to guide a user toward a target direction in space without visual cues. The term draws an analogy to water dowsing, where a divining rod supposedly reacts when pointing toward the target. In tactile dowsing, a handheld…

Tactile Drawing(also: Tactile Picture Making)

The process of creating raised-line images that can be perceived through touch rather than vision. Tactile drawing can be done by blind or sighted people using methods such as drawing on swell paper with a thermo pen to produce immediately raised lines, using a stylus on plastic…

Tactile Ideation(also: Tactile Design Workshop, Non-Visual Ideation)

A design methodology adapted for people with visual disabilities that replaces visual ideation techniques (such as sketching, post-it notes, and ideation cards) with tactile and auditory alternatives. Techniques include using physical objects as conversation prompts…

Tactile Image Exploration(also: Tactile Graphics Exploration, Haptic Image Exploration)

Tactile image exploration is the process by which blind or visually impaired users perceive and interpret graphical content through touch, typically by moving their fingers across raised-line drawings, embossed diagrams, or haptic displays. Unlike visual perception, which allows…

Tactile Maps(also: Tactile cartography, Raised-line maps)

Maps produced in physical, raised-relief form — typically on swell paper, vacuum-formed plastic, embossed paper, or 3D-printed substrate — so that blind and low-vision users can read geographic information by touch. Tactile maps use a constrained vocabulary of lines, textures,…

Tactile Paving(also: Tactile Ground Surface Indicators, TGSI, Detectable Warning Surface)

A system of textured ground surface indicators installed on footpaths, train platforms, and building floors to assist pedestrians who are blind or have low vision with navigation and hazard detection. Tactile paving typically uses two patterns: raised dots (truncated domes) to…

Tactile Perception(also: Cutaneous Perception, Touch Perception)

Tactile perception is the process of perceiving and interpreting information through the sense of touch, encompassing both cutaneous perception (sensing through the skin in a stationary process, detecting texture, pressure, vibration, temperature, and pain) and haptic perception…

Tactile Rendering

The process of converting visual or spatial information into a tactile format that can be perceived through touch by blind or visually impaired users. Tactile rendering involves decisions about how to represent 3D objects, spatial relationships, depth, and visual attributes…

Tactile Signage(also: Tactile Signs, Touch-Readable Signs)

Signs designed to be read by touch, typically featuring raised lettering, Braille text, or tactile symbols. Required in many jurisdictions under accessibility legislation such as the Americans with Disabilities Act (ADA), tactile signage is placed at standard locations like room…

Talking Browser(also: Talking Web Browser, Speaking Browser)

A historical term for a specialised web browser that converts on-screen content into synthesised speech, enabling blind and low-vision users to browse the web through audio rather than through a separate screen reader layered over a visual browser. Talking browsers such as IBM…

Talking Signs(also: Talking Sign)

An assistive technology system that uses infrared (IR) frequency modulated voice signals to transmit spoken information about signage to people with vision loss. Developed by the Smith-Kettlewell Eye Research Institute in 1992, Talking Signs broadcast recorded messages that can…

The vOICe(also: vOICe)

One of the earliest and most widely studied visual-to-auditory sensory substitution devices, developed by Peter Meijer in 1992. The vOICe converts camera images into sound by scanning left to right, mapping horizontal position to time, vertical position to audio frequency…