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Telepresence - Introduction, Enabling Technology for, Telepresent Location Technology, Telecommunications Link, Applications, Telemedicine, Hazardous and Hostile Environments, Entertainment

remote presence operator site

Xiaojun Shen and Shervin Shirmohammadi
University of Ottawa, Canada

Definition: Telepresence, also called virtual presence, is a technique to create a sense of physical presence at a remote location using necessary multimedia such as sound, vision, and touch.

Introduction

The concept of Telepresence may come from science fiction since science fiction writers have described conceptual versions of virtual reality (VR) and telepresence for decades. The term “telepresence” was coined by Marvin Minsky in 1980 in reference to teleoperation systems for manipulating of remote physical objects. According to Witmer and Singer “(Tele)presence is defined as the subjective experience of being in one place or environment, even when one is physically situated in another”. Telepresence, also called virtual presence , is basically a technique to create a sense of physical presence at a remote location using necessary multimedia such as sound, vision, and touch. This is a networked paradigm by nature, and multimedia communications is used for the transport of information between the user and the remote site. The sense of presence is achieved by generating sensory stimulus so that the operator has an illusion of being present at a location distant from the location of physical presence. Unlike conventional concept of VR that is defined as a new medium to experience presence in a virtual space, telepresence emphasizes the interaction between people and remote site and enables people who are immersed in telepresence systems to act and receive input as if they were at the remote site. Its examples cover applications from the fields of telemedicine to remote surveillance, entertainment, education and other applications in situations where humans are exposed to hazardous and hostile environments. Both telephone and videoconferencing allow for limited types of telepresence since people’s voice or video can be there without the person being physically there, while some forms of VR may enable a greater range of interactions. Telepresence systems that incorporate successful force-feedback components can be extremely helpful for a variety of applications, for example, space operations such as Robonaut, the robotic astronaut that is now in development. With the benefits of telepresence system, Robonaut can be deployed in difficult or hazardous situations with the replacement of an astronaut, while its operator, safely housed on a nearby spaceship or even on the earth, controls its actions in a fluid, intuitive fashion. Figure 1 demonstrates the concept of remotely controlling Robonaut’s operations.

Enabling Technology for Telepresence

The term “tele-presence” literally illustrates two layers of implications: people are virtually present at the remote site, and that presence is “tele” i.e. distant. The implications lead to two essential components in telepresence systems: telepresent location and communication . Telepresent locations indicate the locations in which the users are virtually present. Standard locations vary from conventional VR to augmented reality (AR) and to real world environments. The interactivity between host and remote locations is accomplished via network link. It is generally accepted that there are three independent aspects of presence which contribute to achieving a sense of remote telepresence:

  • The extent of the sensory information. It is necessary to provide the operator with the same level of sensory information that they would receive if they were actually present at the remote site.
  • Control of sensors. It must be possible to move the sensing devices around the environment as if the operator was at the remote site.
  • The ability to modify the remote site and actively interact with it.

To achieve the ultimate sense of presence at a remote site requires the full combination of all these aspects and is essentially what most telepresence systems are attempting to create. The telepresence aspect of the teleoperator is to provide sensory feedback to the operator in such a way that the feeling of sensory presence is conveyed. A high degree of sensory presence is required when the operational tasks are wide ranging, complex and uncertain, for instance, in hazardous or difficult environments.

Telepresent Location Technology

Telepresence enables people physically located in their host location to behave and receive stimuli as though at a remote site. The technology used in host location is similar to what is applied in conventional VR and AR applications. The difference is that, in VR and AR applications, users are immersed in a computer synthesized environment (VR) or a combination of a real location and supplemental objects or information (AR), whereas, in telepresence, users are immersed in a remote real world. Multimedia sensory feedback is required to achieve this, which takes multiple modalities including haptic/tactile, sound, vision or even olfactory.

A visually coupled system utilizes a display system such as a Head- Mounted Display (HMD). These systems are worn over the eyes of the user and generally only give the impression that the user is immersed within the environment displayed in the images. HMDs enable a higher degree of user immersion compared with standard monitors or television displays. Haptic interfaces bring more and more realism to telepresence. Olfactory displays could also be used but practical commercial systems have yet to be developed.

Control is a key element of telepresence operations to create vivid awareness. By tracking the operators head position with a sensor, the remote camera system can be controlled in such a way that the head motion is replicated in the remote environment. The effect of this relationship between the operator and the remote mechanical system is to further enhance telepresence and to allow the operator to concentrate on the task itself instead of how to achieve it.

Most of the equipments deployed at remote locations focus on acquisition of the surroundings’ information, modification of the remote site and interaction with it.

Typically, these equipments include: pan/tilt monoscopic and stereoscopic camera platforms, other sensor platforms including microphones and touch/force feedback sensors, slave manipulators and grippers, and mobility providers such as wheeled or tracked vehicles. Mostly, the approach of capturing/compressing video/sound in real time is in demand due to the bandwidth limitation of telecommunication link.

Readers are referred to two other chapters in this book for further information: Virtual and Augmented Reality, and Tele-Haptics.

Telecommunications Link

Although any available telecommunication links may be used in a telepresence system, specific systems dictated different demands on network configurations, such as bandwidth requirements, and the sensitivity to network impairments (latency, jitter and packet loss). For instance, in a telepresence system enhanced with haptic interface, the standard implementation requires that haptic information (force/kinematic data) to be transferred over communication link between home and remote locations. Since network latency adds phase lag to the signal, this lag limits the effective bandwidth of closed haptic control loop and may result in an unstable haptic display. Such instability poses a safety threat because of the relatively large force-generating capability of the hardware. Significant research results have been achieved in teleoperation domain to deal with varied network delays.

Telepresence Applications

The flexibility of telepresence system allows a myriad of applications. The following is a selection of some of the current telepresence systems, both completed and under investigation. Each can be fully realized with the latest technology, and most can operate, albeit at a reduced service level, over the existing network.

Telemedicine

Telemedicine is the delivery of healthcare services, where distance is a critical factor. For example, in a battlefield scenario, the first hour after a soldier has been injured is critical. Telepresence could be used to transport the “presence” of the medical doctor, surgeon and consultant to hospital operating rooms or the scenes of battlefield to assist paramedics. This would facilitate the more effective use of an increasingly limited resource – the medical specialist. The armed forces have an obvious interest since the combination of telepresence, teleoperation, and tele-robotics can potentially save the lives of battle casualties by allowing them prompt attention in mobile operating theatres by remote surgeons, as illustrated in Figure 2.

Hazardous and Hostile Environments

Many other applications in situations where humans are exposed to hazardous situations are readily recognized as suitable candidates for telepresence. Mining, bomb disposal, military operations, rescue of victims from fire, toxic atmospheres, or even hostage situations, are some examples. Remote controlled robotic devices are being used to detect and remove bombs and land mines. By providing the operator the ability to feel what the robot is feeling, the detection/removal task can be done more efficiently and safely.

Entertainment

Telepresence systems could be incorporated into theme or nature parks to allow observers to travel through coral reefs, explore underground caves, or in amusement parks the elderly or infirm could experience the thrill of live roller coaster rides without the associated risks. Figure 3 shows an example of a telepresence musical performance with musicians at two remote sites: Stockholm’s KTH Royal Institute of Technology in Sweden and Stanford in the United States.

Remote Surveillance

Security forces throughout the world are increasingly resorting to video recording as a means of crime certification and prevention. Telepresence is one of the logical developments in this trend, with each security officer linked visually and orally at all times to headquarter. Sensor platforms operating autonomously in robotic mode could monitor sensitive areas. They could use software algorithms that would identify, for example, intruders. They would then proceed to track these intruders while sending an alert to a human operator requesting attention. The operator would be wearing a HMD helmet and become telepresent at the remote location and take over control of the sensor platform. This would then allow the operator to investigate more.

Teleconferencing

Teleconferencing literally means “conference at a distance”, where multiple geographically dispersed users have a meeting of some sort across a telecommunications link. It is one of the uses that the integral display on the desk could be put to, producing a life size head-and-shoulder image of the remote user. The large size of the screen ensures that peripheral vision is substantially filled, thus creating the illusion of “being there”. The high definition of the display allows it to be multi-tasked during teleconferencing as the main viewer and a computer monitor. By using an infra red light pen, the screen can also function as an electronic white board, allowing multiple participants to interact in the same media-space in real time. People sitting at desks thousands of miles apart can thus come together to realize a real time working environment that closely mimics reality.

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