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Glossary of Telepresence Terminology

Telepresence: The experience or impression of being present at a location remote from one's own immediate environment. For more information, see our Telepresence pages.

Teleoperation: Direct and continuous human control of a teleoperator (Sheridan)

Telemetry: Measurements and information recorded from a remote device and transmitted for use elsewhere.

Telerobotics:

Telesurgery: Use of telepresence and/or teleoperation techniques allowing a surgeon to operate at a location remote from his real physical location. Sometimes also used to refer to remote medical diagnosis of certain conditions, useful in areas where access to medical facilities is scarce.

Remote Site: The location of the sensor platform in a telepresence system - the location which the user at the local site wishes to be telepresent in.

Local Site: The location of the human user in a telepresence system, and the equipment contained therein for realisation of the telepresence experience and communication with the remote site. Also sometimes referred to as the Home Site.

Anthropomorphic: To have attributes pertaining to human function and form; thus an Anthropomorphic Robot Head is a robot head which bears a significant functional resemblance to a human head.

Anthropometric: Having dimensions akin to that of human form.

Video Compression: The encoding of real-time video so that it may be transmitted over a low bandwith communications link. One example used by us is the Strathclyde Compression Transform (SCT).

Audio Compression: The encoding of audio information in order that it use less bandwidth or storage space on digital media whilst retaining essential audio quality. Popular examples of audio compression techniques include GSM and MP3

Head Mounted Display (HMD): A video (and sometimes audio) reproduction device worn on the user's head, usually to provide an immersive VR or telepresence experience.

Shutter Glasses: Glasses worn by the user allowing him to perceive a 3D image when looking at an appropriately configured display system such as a computer monitor or projection system. Shutters in the glasses corresponding to each eye are synchronised with the display system, which alternately presents a left or right eye image. A problem with this system is that the refresh rate presented to the user is effectively halved, which can result in visual fatigue.

CAVE System: An immersive audio and visual environment created by the Electronic Visualisation Laboratory, allowing a user to explore VR and Telepresence environments. The CAVE is a room which the user is present in, on which at least 4 surfaces have realtime imagery projected upon them. The experience is further enhanced by Shutter Glasses.

Stereo Vision: A vision system which replicates the way the human visual system works, allowing perception of depth via stereoscopy.

Virtual Reality (VR): The creation and display of synthetic dynamic scenes and situations, often with the goal of providing a close enough rendition of the scene to convince the observer that they are actually there. In practice, the term has been applied to simulations that do not even come close to this goal. For higher end applications, use of immersive video, audio and even haptic feedback has been employed.

Augmented Reality (AR):

Refresh Rate:

Robot Head:

Communications Link:

Control Software:

Control Hardware:

Active Vision:

ISDN: Acronym for Integrated Services Digital Network, an international communications standard allowing bandwidths between 64Kbps and 1.5Mbps over digital telephone lines. A domestic ISDN line such as those offered for home use in the UK will generally offer two modes of use; a single 64Kbps channel or combined dual channels giving 128kbps.

Immersive: A term used to refer to certain types of sensory reproduction systems used in VR and Telepresence where the user actually becomes part of the experience to the exclusion of their immediate reality, as opposed to being a mere observer. For example, a user using a Head Mounted Display or CAVE system would be immersed in the experience, whereas someone viewing a remote location on a simple computer monitor would not be.

Stereo Sound: A method of sound recoding and reproduction using two or more audio channels to reproduce spatial depth in the sound.

Binaural Sound: A twin eared recording method, often using a dummy head to simulate human hearing effects.

Bandwidth: The amount of data a communications link can transmit in a given period of time. Generally measured in bits per second.

Simulator Sickness: A symptom caused by the phase lag in a system, generally resulting in the user feeling nauseous due to differences in the provided visual and spatial information. Not entirely dissimilar from motion sickness, where one's visual system indicates movement, but the messages from the inner ear tell the mind that one is stationary.

Update Rate: The ability of a tracking device to output position and orientation information to an output port.

Phase Lag: The ability of the tracking system to determine an object's position within a given period of time after a change in object position, determined by the sum of update rate and latency. Can lead to a symptom known as simulator sickness since there is a conflict between what the eye sees and the inner ear perceives.

Latency: The rate at which the acquisition portion of the system can acquire new data. Summing update rate with latency results in the phase lag response. 

Pan: From a human viewpoint, moving one's head from left to right or vice versa constitutes a panning movement. More specifically, a pan is a rotation in the horizontal plane. Sometimes referred to as azimuth.

Tilt: To move an item, such as a camera or human head, in an upwards or downwards rotation. Technically, a camera rotation about an axis perpendicular both to the pan axis and the optic axis.

Roll: In human terms, used to indicate side to side rotational movement performed by a device such as a camera platform or human head. Specifically, rotation about an axis parallel to the optic axis.

Zoom: The ability of a camera lens to change its focal length in order to view objects at varying distances while retaining a sharp focus.

Camera Vergence: The ability of two or more cameras to converge their optic axes on a gaze point in 3D space. Think of two human eyes focussing on an object moving nearer and further away from said human.

Camera Version: The ability of two or more cameras to verge on a gaze point which may be moved in the pan plane without neck movement.

Camera Platform: A device for mounting a camera on, usually movable. This can be a simple pan and tilt mechanism, or have an additional roll axis to increase anthropomorphism, depending on the demands of the application. In the future we envisage greater use of solid-state camera platforms involving few or no moving parts.

Olfactory: Of or pertaining to the sense of smell.

Haptic: Relating to the sense of touch.

Tactile: Relating to the sense of touch, but at a greater level of detail than that implied by haptic. For example, a tactile sensor may have the ability to detect high level physical details of an entity, such as texture.

Force Feedback:

Exoskeletal: To have a skeleton on the outside of the body as opposed to the inside; insects are one type of creature exhibiting this feature. 

Strathclyde Compression Transform (SCT): A form of video compression particularly effective over low bandwidth communication links. For more information on this technology please visit the SCT web pages.

Master Slave System:

Robot Arm:

Degrees Of Freedom (DOF):

Closed Loop Control System:

Stepper Motor:

Dummy Head: An anthropomorhpic and anthropometric head used to accurately mimic human audio perception for binaural recording and hearing research.

GSM:

MP3: Abbreviation of "MPEG Audio Layer 3", a method of audio compression using perceptual coding techniques. This allows high compression rates at high quality through use of knowledge of the audio properties of the human ear. Commonly used at bandwidths of between 8kbps (telephone quality) and 128kbps (CD quality).

H263: An ITU standard video compression format used for modem and ISDN bandwidths.

Hyperstereoscopy:

Hypostereoscopy:

Interocular Distance:

Orientation: The rotational state of an object relative to a set of reference axes. The orientation of an object free to move in three dimensions has 3 components, sometimes referred to as pan, tilt and roll.

Tracking Device: A device which reports one or more factors concerning the state of an external entity. For example, the Polhemus 3Space Isotrack is a 6 DOF tracking device which reports the orientation and position of a small sensor. All tracking devices are subject to phase lag.

Proprioceptor: A sensory receptor which receives stimuli from within the body, specifically one that responds to position and movement.

LCD: Acronym for Liquid Crystal Display, a low power type of display found on a myriad of devices from pocket calculators and digital watches to laptop computers and head mounted displays.

Copyright 2004 Transparent Telepresence Research Group