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.
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
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):
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
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
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
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
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
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.
Exoskeletal: To have a skeleton on the
outside of the body as opposed to the inside; insects are one type of creature exhibiting
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:
Degrees Of Freedom (DOF):
Closed Loop Control System:
Dummy Head: An anthropomorhpic
and anthropometric head used to accurately mimic human audio
perception for binaural recording and hearing research.
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.
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
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.