From 3D to VR and further to Telexistence
Susumu Tachi*
Keio University / The University of Tokyo

ABSTRACT2

The history of 3D elucidates that it has a thirty year cycle of evolution.
Further, it was discovered that VR (virtual reality) and AR(augmented reality) evolved almost a decade after the 3D crazes
occurred. This leads to the conjecture that the next VR and AR craze
will be in the 2020s. AR augments the sense and intellect of a human.
Human augmentation or augmented human (AH) augments humans
not only in their senses and intellect but also in their motions andabilities to transcend time and space. Human augmentation in timeand space is termed as telexistence. In addition, the evolution oftelexistence is reviewed along with a glance at its future prospects.

3D and virtual reality (VR) are two closely related areas ofscience and technology. As shown in Figure 1, an examination of
the history of 3D reveals that 3D crazes have occurred every thirty
years. It is also apparent that a VR craze has emerged after each
3D craze. Although historically 3D first appeared in the 19th
century, the true dawn of the technology did not arrive until the
1920s. After this early stage, the first 3D craze came in the 1950s,
when the term “3D” was first used and the term “3D craze”
became widespread. Subsequently, there was a second 3D craze inthe 1980s, followed by a third in the 2010s. The dawn of VR camein the 1960s, 10 years after the first 3D craze. The first VR craze
was observed in the 1990s, 10 years after the second 3D craze.
Since this trend shows VR crazes occurring approximately 10
years after 3D crazes, the author expects a second VR craze tooccur in the 2020s (Tachi conjecture).

Keywords: 3D, virtual reality, VR, augmented reality, AR, humanaugmentation, augmented human, AH, cyborg, telexistenceIndex Terms: A.1 [INTRODUCTORY AND SURVEY]; I.2.9[Robotics]: Operator interfaces; I.3.7 [Three-Dimensional Graphics
and Realism]: Virtual reality; H.4.3 [Communications Applications]:
Computer conferencing, teleconferencing, and videoconferencing

1

3D MOVES IN 30-YEAR CYCLESINTRODUCTION

Virtual reality (VR) captures the essence of reality; it represents
reality very effectively. VR enables humans to experience eventsand participate in a computer-synthesized environment as though
they are physically present in that environment. On the other hand,augmented reality (AR) seamlessly integrates virtualenvironments into a real environment to enhance the real world.
AR achieves human augmentation by enhancing the senses andintellect of humans. Augmented human (AH) augments humans intheir motions and their ability to transcend time and space besides
enhancing their senses and intellect. Cyborgs and telexistence
would mark the peak of AH development.
Telexistence is a concept that can free humans from therestrictions of time and space by allowing humans to exist
virtually in remote locations without travel. Besides, it can enableinteractions with remote environments that are real, computersynthesized, or a combination of both.
This keynote reviews the past and present of 3D, VR, AR, AH,
cyborg, and telexistence to study the mutual relations and thefuture of these technologies. Further, it introduces the recent
advancements and future prospects of telexistence. TELESAR IV,
which is a mutual telexistence system, TELESAR V, which is
known for achieving haptic telexistence, and TWISTER, which isa telexistence wide-angle immersive stereoscope that provides afull color autostereoscopic with a 360 degree field of view, havebeen given special emphasis.

* tachi@tachilab.org

Figure 1: Evolution of 3D and VR.

2.1 Origin of 3D
3D originally began in 1838 with the invention of binocular stereo
in the UK [1]. It was the brainchild of Sir Charles Wheatstone,
known for the invention of the Wheatstone bridge used in the fieldof measurement. Binocular stereo was the first stereo viewer
technology presented to the Royal Society of London in the formof a mirror stereoscope. It was subsequently refined in 1849 by arenowned Scottish physics professor Sir David Brewster, whochanged the mirrors used in a binocular stereo to prisms. Oliver
Wendell Holmes in the US further modified Brewster’s
refinement into a practical product that enjoyed worldwide
popularity. However, even Holmes’s product only showed
pictures or photos in three dimensions when the user looked
through an apparatus resembling binoculars. It was unable toshow movement and the observed 3D images were quite small;therefore, the 3D images that could be seen looked like miniatures.
2.2 Lead-up to the Dawn of 3D
In 1853, a method for generating 3D images called “anaglyph”
was created [2]. This method applied red and blue filters to the left

and the right eyes, respectively, and showed each eye a red or blue
image having parallax. Subsequently, the filter colors werechanged to red and green (a better match for the physiologicalstructure of the human retina than red and blue).
Magic lantern slideshows first appeared in Germany in 1858.
These slideshows enlarged the screen but still had no movement.
Images first started to move with the 1895 invention of what is
considered the first moving picture technology, thecinématographe Lumière. Although Thomas Edison had actually
invented and demonstrated in public a moving picture technology
called the "kinetoscope" in 1891, it was still a technology that
required the user to look through a peephole. Inspired by Edison,
the Lumière brothers created a technology that replaced thepeephole with a large image projected onto a screen that could beseen by multiple viewers at once—the cinématographe Lumière.
Although the cinématographe Lumière itself was not 3D, it was
combined with anaglyph to become 3D, leading to the dawn of 3D
in the 1920s.
2.3 Dawn of 3D
Practical anaglyph-format 3D movies first appeared in the 1920s.
Although the format enabled 3D projection, there was a highdemand for a technology that would show 3D images in natural
color instead of the anaglyph’s red and green.
The technology created to meet this demand was time-division
3D movies. Lawrence Hammond (of Hammond Organ fame)created 3D images by rapidly switching between the right and theleft eyes using a mechanical shutter. Hammond invented a systemthat used a disc-shaped shutter that spun to rapidly switch the lightreaching the right and left eyes. At the same time, a projector wassynchronized to the shutter disc and switched the right and left eye
images, projecting different images to the right and left eyes andmaking the image appear 3D. This technology is a very wellconceived 3D system even by today’s standards. Although it
amazed large numbers of viewers, unfortunately, it soon fell into
disuse because of its poor cost effectiveness [3].
2.4 First 3D Craze
The Polaroid format (a polarized light-based format) came into
widespread use in the 1950s. Polarized stereoscopic pictures
themselves had first been demonstrated in 1936 by Edwin H Land.
The format came into widespread use in the 1950s, giving rise to a
3D movie craze that lasted from 1952 to 1955. Linear polarization
was used as the polarization format. The term “3D” is said to havebeen coined at this time. The advances that enabled 3D
technology were polarized stereoscopic glasses and a silver screenthat could preserve polarization. However, the 3D craze did notlast long. Despite reaching a fever pitch at one point, it was overin two or three years. However, even though the craze passed, thetechnology associated with it developed by leaps and bounds witheach new craze, and since then, the field of 3D technologies hasgrown steadily.
2.5 Second 3D Craze
Thirty years after the 1950s, the 1980s saw a second 3D craze.
Instead of linear polarization, the method used was circularpolarization, which enabled the viewer to retain the 3D effect even
if the head was tilted. This method made 3D images very easy toview, as there was no restriction on head movement; thus, themethod was widely used for projecting movies and videos at
events such as expositions.

2.6 Third 3D Craze
The third 3D craze comprises 3D movies now complemented by
3D TV, which got fully underway in 2010. This craze appears tohave died down fairly rapidly, as is the fate of 3D. However,today’s 3D display technology is expected to continue spreading
to various areas. It is expected to serve as a major step toward thesecond VR craze that should follow the current 3D craze, which is
how it is positioned.
2.7 Reason for the Short Lifespan of 3D Crazes
Why are 3D crazes always so short-lived? The reason is that sincethe 3D technology aims to reproduce the visual experience of thereal world, an ideal 3D technology cannot be achieved without
perfecting VR. Figure 2 illustrates why this is true. In two
dimensions, the size of an object and the distance to it cannot be
determined uniquely, and they are arbitrarily determined by ahuman viewer by his/her estimation. Therefore, when viewing a
2D photo or movie, the viewer estimates the object’s size anddistance to it from the size of a known object using his/her pastexperience. Thus, human figures are estimated to be of a humansize, however small the 2D image is.
As soon as a photo or movie is created in 3D, both the size ofan object and the distance to it become uniquely determined.

Figure 2: Both the size of an object and the distance to it become
uniquely determined in 3D.

When an entire scenery of a person shot with a stereo camera isviewed on 3D displays of different sizes, the same person in theimage will appear large when the 3D display is large and willappear small when the display is small. This problem is inevitablefor 3D.
In order to have natural 3D such as that observed in the realworld, only part of the entire scenery captured by the camera must
be displayed when the display is small. The display cuts out aportion of the entire 3D world; therefore, natural 3D projection
requires only a portion of the entire scenery that was captured by
the camera when the image is viewed on a display with a smaller
angle of view than the camera that it was shot with. Doing so
ensures that sizes and distances are kept the same as in the actual
scene. To view the entire scenery on a small display, the display
must be moved left/right and up/down.
As mentioned before, discrepancy occurs as soon as the entire
image is crammed onto a small display without trimming.
Distances and sizes are no longer accurate, and the result starts toresemble the world as depicted in a miniature. However, thisproblem does not exist in 2D as mentioned before. When the sameimage is sent to small and large displays such as a smartphone
screen and a large TV screen, the viewer infers the original sizesof the subjects in their head, enabling them to correctly read theimage without difficulty. When a broadcast becomes 3D, thismethod of 2D is no longer possible. When the same content is sent
to a smartphone and a large-screen TV, the same person canappear to be a dwarf or a giant. This problem results from theessential nature of 3D per se.
Therefore, it is ultimately not possible to achieve well-defined
3D without the knowledge of VR. As with the current technology,
the objects appear unnatural, and also, the result causes eyestrain.
Movies released in theaters are shown on large screens of roughly
the same size; therefore, well-made movies such as Avatar createdby the director with a solid knowledge of 3D projection, James
Cameron, appear perfectly natural when viewed in a theater.
However, when the same movies are viewed on a display with thesize of a household 3D TV, the result starts to look very unnatural.
Moreover, pseudo-3D created by reworking 2D is unnaturaleven when viewed on a large screen in a theater. The reason isthat pseudo-3D is created by shooting the movie in 2D instead of
3D. Zooms and other techniques commonly used in 2D are
entirely useless in 3D. Objects in 3D should become larger whenthe viewer moves toward them or when they approach the viewer;
hence, zooming (in which objects do not move physically closer
to the viewer) is a technique that only works in 2D and is uselessas well as harmful for 3D. In light of all these issues, 3D movies
can only succeed when shot with a thorough knowledge of VR.
Unnatural 3D can therefore look more unnatural than 2D or cause
eyestrain.
Further, poorly shot 3D movies are rejected by the humansensory organs. As humans, we spend our lives in the 3D realworld; hence, our sensory organs are highly attuned to it, enabling
us to instantly and instinctively recognize and reject poorly
executed 3D projections.

considered VR. In contrast, VPL Eyephone worked together witha device called a data glove to project the user into a VR world. In
other words, the user entered the VR world.
Further, the user could view his/her own hand in this world,which was temporally and spatially synchronized to his/her
movements, creating an impression of being immersed in thisworld.
The VPL system in 1989 was the one that attained the threeelements of VR, i.e., life-size 3D space, real-time interaction, andself-projection (Figure 3). On the other hand, Susumu Tachi
proposed the concept of telexistence in 1980, and in 1988, heconstructed a system attaining the abovementioned three elements,
known as TELESAR (Telexistence Surrogate Anthropomorphic
Robot). In this case, user hand operations and other aspects ofsystem performance were verified both in real-space and in CG
environments. Figure 3 illustrates the three elements of VR [5].

3

In the 1990s, another useful system incorporating the three VR
elements was completed. Known as CAVE (CAVE Automatic
Virtual Environment), the system was exhibited and presented by
Carolina Cruz-Neira, Thomas A. DeFanti, and Daniel Sandin at
SIGGRAPH in 1993 [6]. The system turned the room itself into a
3D interactive environment. Subsequently, a five-surface systemcalled CABIN was created in Japan by a team led by Michitaka
Hirose. When viewing three dimensions, CAVE switched theimage using LCD shutter glasses. Coming 70 years after
Hammond’s 1922 mechanical shutter, it replaced the mechanicalshutter with an LCD shutter. Making the shutter electronic using
an LCD made it easier to use than the previous mechanicalversion, enabling commercial release. Incidentally, most of
today’s 3D TVs and 3D movies use this LCD shutter method.

VR MOVES 10 YEARS AFTER 3D MOVES

3.1 Dawn of VR
In the 1960s, 10 years after the first 3D craze, Ivan Edward
Sutherland created 3D images using computer graphics (CG).
Sutherland displayed CG images in the real world as augmented
reality (AR), although the term AR had not yet been coined. The
images were linked to human movements to enable displays of 3Dimages incorporating the viewer’s perspective. This technology
was presented in 1968 in a paper titled “A Head-Mounted Three
Dimensional Display [4].” Sutherland’s head-mounted display
came 130 years after the Wheatstone stereoscope in 1838.
Although the images themselves were still line drawings, they
were expressed using computer graphics, and since objects wereseen from the viewer’s perspective in correspondence with viewer
head movements, the technology has been considered the
beginning of VR (although again, the term VR was not in use atthat time). Sutherland is therefore considered to be the father ofboth CG and VR.
3.2 First VR Craze
The first VR craze came in the 1990s, 10 years after the second
3D craze. The craze was initiated by a renowned head-mounted
display (HMD) product called Eyephone that was jointly
developed by VPL and NASA. It was created in 1989,
approximately 20 years after Sutherland. Sutherland’s systemenabled the user to move his/her head independently but did notgive the impression of being in a separate location generated by
the computer. In today’s terminology, Sutherland’s head-mounted
3D display was an AR system that showed the real world on a seethrough display, and only created an environment with artificial
computer-generated objects added to the real world that the user
occupied. Therefore, it still did not go sufficiently far to be

Figure 3: The three elements of virtual reality and/or telexistence.

3.3

Roots of VR Advance from Several fields in the
1980s
The roots of VR rose from several fields during the second 3D
craze of the 1980s. As shown in Figure 4, researchers such as
Scott Fisher advanced VR in the context of virtual displays andvirtual consoles. In the field of CG, the progression proposed by
Sutherland is as follows: CG→ 3D CG → real-time 3D CG →real-time interactive 3D CG [5]. The idea of making 3D versionsof applications such as CAD was advanced by Frederick Brooks,
Jr. In the field of art, Myron Krueger and others coined the term
“responsive environment” for interactive art.
In the field of computer simulations, researchers such asThomas Furness led efforts to propose a “super cockpit” thatfurther refined flight simulators enabling operations with the same
feeling as operating an actual aircraft. Immersive communicationbased conferencing applications driven by conventional phones
and video phones, and immersive teleoperation applications
giving users the experience of being at a particular location, suchas telexistence and telepresence, were all created in the 1980s [5].
These applications were refined separately and independently in
different fields, without much knowledge of similar trends inother fields.
Amid these developments, a conference was held in Santa
Barbara in 1990. Letters arrived from an MIT-affiliatedengineering foundation. They came by regular mail (air mail), notby email as is common today. They contained an invitation urging
attendance at a research gathering of teleoperators and virtualenvironment researchers. Leading researchers from several
different fields came together in Santa Barbara, presented theirresearch, and held brainstorming sessions and discussions.
As they shared their research, they found many common
elements across different fields. Completely different fields wereseeing a variety of advances that all had a very similar aspect incommon. The similarity was the pursuit of life-size 3D. Moreover,
the type of 3D being sought was interactive 3D that could change,
react, and morph in response to human movements.
The researchers were also looking for technology that enables auser to experience the sensation of being in a computer-generated
environment or a remote environment with a seamless link
between the user and the environment. Seen from this perspective,
research that at first glance appeared to be different for different
fields was actually pursuing the same goal. Thus, it is clear thattechnology originating in one field could be applied to other fields,
and that in terms of the academic field, the goals being sought
formed a single unified academic discipline.
During the conference, the participants reached a consensus thatdevising a name for this field (VR: virtual reality) would help
advance this discipline. They also decided to publish Presence (anMIT scientific journal). The 1990 Santa Barbara Conference wastherefore the “big bang” that marked the first moment of VR—the
inception of the academic field of VR.

meet the desired goal; hence, humans who are experiencing thethus created VR will experience the same effect as from reality.
Therefore, a VR system with the essence of reality provides thesame sensations as reality and produces in humans the same
effects as those produced by reality per se.
3.5 The three elements of VR
As mentioned before, there are three elements required for thecreation of VR. The first is a 3D space that maintains the distances
and the size of a real space. The second is real-time interaction
with this space. The third is self-projection, which assures that theuser’s real body coincides spatially with the user’ virtual body andwith full synchronization. This requires the existence of a virtual
body in the virtual environment that represents the user. For
example, a very important aspect is that the user’s hands in thegenerated space exist at the user’s actual location and that they
move in conjunction with the user’s hands. Hands that look thesame must move in spatial and temporal synchronization. Being
able to see and touch target objects that interact with the hands
gives the user the sensation of being inside the virtualenvironment—of existing at that location. Therefore, the threeelements of VR are life-size 3D space, real-time interaction withthis space, and self-projection into this space.
3.6 VR milestones
Figure 5 shows the major chronological milestones in thedevelopment of VR. In 1989, VPL released Data Glove andEyephone, and the term “VR” became widespread. Subsequently,
the Santa Barbara Conference was held in 1990, and theInternational Conference on Artificial Reality and Telexistence(ICAT) was held in Japan in 1991. (The use of “artificial reality”
instead of “virtual reality” in the conference title is an interesting
historical artifact.) ICAT is the oldest international conference inthe field of VR. In the US, the National Research Council createdthe NRC Committee on VR. In 1993, the Industrial Virtual
Reality Show (IVR) was held in Japan. In USA, two forerunnersof the IEEE VR International Conference were held in 1993, i.e.,
VRAIS (Virtual Reality Annual International Symposium) andResearch Frontiers in Virtual Reality. Further, in 1993, the first
International collegiate Virtual Reality Contest (IVRC) was heldin Japan—a contest by, of, and for students. These events still
continue to be held.

Figure 4: Evolution and development of virtual reality.

3.4 The meaning of “virtual”
According to the American Heritage Dictionary (3rd edition),“virtual” is defined as existing in essence or effect though not in
actual form or fact. The term “virtual” signifies the real more thanit does the imaginary. Naturally, the virtual is not simply the sameas reality itself. Instead, it is the essence of reality, with the same
basic substance and effects as reality. The essence of something is
its basic substance. The essence is not at all absolute and unique—the essence to be embodied will vary to meet the goal at hand. VR
is created by focusing on the aspects that need to be reproduced to

Figure 5: Chronological milestones in the development of VR.

There have also been several milestones in academia. In 1996, theVirtual Reality Society of Japan (VRSJ) was created. In 2001, theIEEE Virtual Reality International Conference was held in Japan,
the first time the event had been held outside the US. More

recently, in 2008, the US National Science Foundation (NSF)
selected “Enhance virtual reality” as one of 14 major
technological goals to achieve in the current century. Therefore, it
can be said that VR is a technology for which continued future
growth is expected.
3.7 Natural 3D converges on VR
When a 3D work has been more or less made although still not in
the final form, the urge that always comes next is to view it fromvarious angles around the circumference other than just the front
or looking around. What inevitably results is a craving for largefield of view 3D that surrounds the viewer as in VR. However,looking at various parts of an incomplete 3D image while moving
the head can lead to the feeling of nausea. Achieving natural 3D
projection is the key to the prevention of nausea, and thedevelopment of VR technology designed with this need in mind isdefinitely inevitable.
Viewing a 3D work also creates the urge to touch 3D objects
and have them feel real. VR is the technology that can satisfy thisurge. However, touching alone is not sufficient to feel it as thoughan object is real. The VR hands corresponding to the user’s hands
need to be in the 3D space and need to move in spatial andtemporal synchronization with the user’s hands. The user will
only feel actually present and touching things in the virtual
location when his/her hands move in synchronization with the VR
hands in the 3D space, and VR objects move as a result of theinteraction with the VR hands. The reasons that 3D crazes do notlast long are that 3D engineers and 3D content creators still do not
fully understand VR and that the VR technology needed to perfect
3D projection has itself not yet been perfected. The first of thesetwo problems can be solved by 3D engineers and 3D content
creators gaining an appropriate understanding of the requisite VR
technology, which they can then apply to their 3D work. The
second can be solved by VR engineers and researchers including
myself by making further advances in VR technology, which isthe duty imposed on us.
VR crazes that started not long after 3D crazes have peaked in
popularity resulting from an understanding of the limitations of
3D technology and a demand for VR to solve them. As described
previously, after the first appearance of true 3D projection in the
1920s, 3D crazes have occurred in roughly 30-year cycles. The
first 3D craze was in the 1950s, the second was in the 1980s, andthe third (current) craze began in 2010. These crazes always end
in two or three years. The two most recent crazes have each been
followed roughly 10 years later by the dawn of VR and then by
the first VR craze. As mentioned before, this pattern suggests thatthe next wave of VR will come in the 2020s. To prepare for it, VR
engineers and researchers need to redouble their efforts at
perfecting VR.
4

FROM AUGMENTED REALITY TO HUMAN AUGMENTATION

VR applied to the real world is known as augmented reality (AR).
AR augments the real world by adding computer-provided
information to it. The computer information is added three
dimensionally to a real-world scene in front of the user in order tocreate a virtual space (information space) and to assist various
human behaviors and movements. Combining a wearable
computer with an eyewear-sized display device, an AR
application verifies the position of people by GPS, obtains
information from a mobile phone, and communicates with an ICdriven ubiquitous computing device to write the information thatit has obtained into the real world. For example, AR can threedimensionally draw a map or contour lines on the real-world
scene in front of the user, display names or descriptions ofbuildings, superimpose a procedure display for a worker, or create
a visual display of hidden pipes in walls. AR is starting to be used
at modern medical sites to assist in diagnosis or treatment by
three-dimensionally superimposing displays of Computer
Tomography (CT), Magnetic Resonance Imagery (MRI), or
ultrasonic images.
This approach to AR is an environment-centered approach ofaugmenting the real world with the world of information.
However, by adopting a new approach centered on the people who
use AR, AR can be used for augmenting people. Such an approach,based on a fusion of the human-centered real world and theinformation world, is called “human augmentation.”
Since human augmentation extends all human abilities, it not only
augments sensory and intellectual abilities but also augments
motion and spatial/temporal abilities. Therefore, humanaugmentation goes beyond the scope of AR, which augments
sensory and intellectual abilities. Not only does humanaugmentation go beyond normal abilities, but it also encompasses
the recovery of abilities that unfortunately have been lost.
Figure 6 illustrates the recovery and extension of humansensory, intellectual, motion, and spatial/temporal abilities.

Figure 6: Human augmentation.

Human augmentation users are known as “augmented humans”(an annual Augmented Human International Conference has been
held since 2010). Augmented humans (AHs) are similar to thecyborgs that have been common in science fiction for many years.
However, since the term “cyborg” has been so overused in science
fiction novels and comic books, relatively few people are aware of
its origin as a genuine scientific term.
The term first appeared in the September 1960 issue of
Astronautics, in an article titled “Cyborgs and Space” by Manfred
Clynes and Nathan S. Kline [7]. The article describes a systemusing a Rose-Nelson osmotic pump to make continuous
subdermal injections of chemicals into rats at a slow, controlledrate without the organism’s awareness. Such a system, able toorganically link an organism and a machine, was dubbed a“cybernetic organism”—“cyborg” for short. The term“cybernetics” was famously coined earlier by Norbert Wiener in
his book of the same name. The book’s subtitle, Control andCommunication in the Animal and the Machine gives a clear
description of the issues that cybernetics deals with. A system thathas reached a state in which an organism and a machine(particularly human and machine) function as a single entity
instead of as separate entities is a cybernetic organism, or cyborg.
As is evident from the origin of the term, a cyborg is a systemwith a strong, organic link between human and machine. In an

augmented human, however, the link does not need to be either
strong or organic. The term “augmented human (AH)” signifies abroader concept that extends from cyborg-like entities to humans
who use wearable devices.
Since ancient times, one of mankind’s two major dreams has
been to have a servant with the ability to faithfully carry out all
tasks that the user commands of it. An age in which this dream isachieved through robots rather than in the unhappy and inhumane
form of slavery is becoming a possibility through advances inmechatronics.
The other dream that humans have had since ancient times is toobtain a thorough training to raise their abilities up to their highest
possible level and become superhuman—the idea of augmenting
and extending human abilities. One embodiment of this dream isseen in the heroes of ancient mythology or in modern-day comicbook superheroes. While robots are mainly linked to human-associal-entity, augmenting and extending human abilities havestrong ties to human-as-individual-entity.
Human’s efforts to make up for the abilities that he/she lacks or
to raise his/her strength to great heights began with the use oftools and weapons. Lacking fangs, ancient human turned to spears
and swords to fight animals. However, tool use only creates a
superficial connection between a human and a tool. While skilled
tool users are said to become one with the tool, tools generally do
not become part of the human body.
In a way, a human’s first experience of becoming a superhero
may have been when he/she first rode a horse. Being able toskillfully control a horse allowed humans to quickly cover vastdistances at will. Modern engine-powered vehicles and private
cars in particular have enabled almost everyone to experience a
taste of what it first felt like to become a superhero. However,there is a fundamental difference between private cars and public
transport that is evident here—while public transport is an
outgrowth of automation technology, private cars are thesuccessors to the horse, or the forerunners of cyborgs and AHs.
Needless to say, a vehicle is an individual entity that does notform an organic link with its driver; therefore, the vehicle and thedriver are not a cyborg. However, the feeling of unity with thevehicle that anyone who has ever driven has felt, and the sensationand freedom of being able to drive to see a sunrise at the beach ona whim may be precisely the mindset of a cyborg. Users who wantto routinely wear mobile devices such as pocket calculators,
pocket electronic interpreters, and mobile PCs are the forerunnersof cyborgs and come close to being augmented humans (AHs).
They are intellectual AHs.
As machines become intelligent and the link between humans
and machine grows ever closer, the potential for supplementing
and expanding the abilities of the individual will increase.
Cyborgs and AHs are entities that have put these abilities tomaximum use.
4.1 Sensory augmentation
Sensory augmentation is the extension of human sensory abilities.
Normal human vision can only recognize a part of the spectrum
known as visible light, which has wavelengths from the violet to
the red end of the spectrum (380 to 780 nm). However, the world
is filled with various other types of light, such as light of shorterand longer wavelengths than humans can perceive. Suchinformation could be captured by sensors worn on the body,
converted into visible light, and immersively presented to ahuman user by superimposing a model of the outside world on it.
For example, a completely dark scene viewed in infrared would beseen as no longer dark. By presenting the information
immersively to the human user, a user in complete darkness could

work as though he/she were in a well-lit environment or could see
objects through smoke.
Another example application might be radiation sensing.
Although radiation is hazardous to humans, we have no naturalability to sense it. Such hazard information could also be captured
by sensors worn on the body and presented to the human user,
enabling the user to avoid hazardous situations while working.
Applications might include giving the user the ability to see an
object inside a wall by presenting them with an internal image
shot beforehand, or to see what is on the outside of a wall by
projecting a real-time image of the outside scene on the wall.
These applications are extensions of the human visual function.
Other applications could extend hearing by immersively
presenting sound of audible wavelengths in place of information
obtained using ultrasound or low-frequency vibrations. The senseof touch could also be extended in a similar fashion. For example,
imperceptibly fine textures and indentations could be magnified
and presented as sensations that humans can feel. Anotherexample is a wearable sensor that could capture its radianttemperature and present it to the user before the user makes directcontact with an object of unknown temperature.
There are also types of human augmentation used forrecovering abilities that have unfortunately been lost. A good
example is a guide dog robot for the visually impaired that was
researched and developed from 1977 to 1983. The final prototype
model was known as MELDOG Mark IV, which enhanced themobility of the visually impaired by providing guide dog
functions. It could obediently guide a blind user in response touser commands, exhibit intelligent disobedience when detecting
and avoiding obstacles in the user’s path, and provide wellorganized man-machine communication not interfering with theuser’s remaining senses [8].
Released in 2005, AuxDeco is another example of a humanaugmentation tool for the visually impaired. A small camera built
into a headband worn by the user acquires an image of theimmediate surroundings, which is preprocessed and then“displayed” on the user’s forehead in the form of tactile sensations
generated by electrocutaneous stimulation. Forehead stimulation
serves as a substitute for the retinal stimulation experienced by thenormally sighted. The forehead is better adapted to thisapplication than other areas of the body since it is easier for theuser’s brain to coordinate the scene with his/her body posture in
response to head movements.
4.2 Intellectual augmentation
It is also possible to intellectually augment humans bysuperimposing various types of information not related to physicalquantities. Intellectual augmentation is almost the same as what is
generally referred to as AR. The only difference is that intellectual
augmentation applications are expressed from a different
perspective—human-centered instead of environment-centered.
As previously described in the section on AR, computer
information is three-dimensionally added to the real world toassist various human conducts and performances. Examples ofintellectual augmentation applications include the following: (1)guiding a walking human user, (2) displaying attributes of abuilding in view, (3) displaying information about the shops andoffices located in a building, (4) displaying the name and otherpersonal information of a person in view, (5) displaying operating
instructions for an apparatus in view, (6) displaying thetemperature of an object in view, and (7) presenting real-time
emergency information.
Another example could be an application that after hearing apiece of music, can display information such as the title or the

composer of the piece in goggles worn by the user, or can whisper
the information in word form into the user’s ear. Anotherapplication could inform the user of what a touched object is madeof.
When a user is operating something, intellectual augmentation
applications could indicate answers to questions of the user or
could provide assembly or cooking instructions to the user while
the task is being performed, superimposing the information on thephysical object that the user is operating.
Wearing an intellectual augmentation system could enable auser to record his/her daily activities to create a “life log.” Thedata could be organized for easy use and stored for many years. It
could be retrieved and used as needed for providing a window into
the past to find out what the user has experienced and learned.
Several of these types of functions have already been
implemented on today’s smartphones. Various apps used on
today’s smartphones could be considered to have reached the levelof apps for intellectually augmented humans if they are modified
from a handheld to a hands-free format by enabling them topresent information in goggles.
4.3 Motion augmentation
Typical examples of devices for augmenting human motion are
cybernetic prostheses such as prosthetic limbs, and orthotic
devices such as walkers. Another typical example is theexoskeleton human amplifiers that were researched and developedin the 1960s.
Exoskeleton human amplifiers were wearable robotic devices
that ensured safety by covering the user in a shell- or armor-likecovering, enabling humans to be placed directly in hazardous
environments. They could also be used for amplifying the user’s
strength. A good example was Hardyman, which was the result ofresearch led by the US Army and General Electric (GE) in
connection with a project called Mechanical Aid for the Individual
Soldier (MAIS). The Hardyman project started in 1966, whose
goal was to enable the user to walk at a speed of approximately
2.7 km/h while raising an object of approximately 680 kg to aheight of approximately 1.8 m.
In exoskeleton human amplifiers, human motion is detected by
sensors, and an exoskeleton-type robot moves in accordance withthe detected movement by using servo control. The robot moved
freely in conformance with human limb movements, while
amplifying human strength.
Despite the large amount of money and the considerable
number of man-hours that went into this research, it ended in
failure. There were several reasons for its failure. One was that thehumans placed in the robots were still in very hazardous
environments irrespective of the amount of armor they wereencased in. A single shield rupture could expose them to a very
hazardous environment. Moreover, a crushing accident caused byan equipment malfunction would result in the human also being
crushed by the robot’s amplified power.
The second reason was that the humans could not do anything
without moving of their own volition. When the machines moved
automatically, the humans were moved along with them. The
humans were forced to be in constant motion while using therobots, making the robots very demanding devices for the humans
to use.
Japan has recently been experiencing renewed interest in
developing exoskeleton human amplifiers, and several productlaunches for applications such as nursing care and agriculture
have attracted attention. In conjunction with research into areas
such as cybernetic augmentation, this technology could lead to thedevelopment of cyborgs.

4.4 Space/time augmentation
The space/time augmentation technology frees humans from theconventional restrictions of space and time, enabling them toeffectively exist in an environment removed from time, space, orboth time and space. In a sense, the technology can make humans
ubiquitous, echoing the concept known as “telexistence.”
Telexistence is a technology that augments humans to givethem the sensation of existing in a location other than the locationthat they are currently in, and enabling them to act freely at thatlocation. For example, a robot placed in a remote location is
operated in synchronization with the user’s body movements. The
user sees from the robot’s perspective, hears what the robot hears,
and feels through the robot’s skin, giving them the sensation of
becoming the robot or of being inside the robot. This technology
gives the user the highly immersive sensation of being at the
robot’s location instead of at their actual location. Moreover,human movements are faithfully conveyed to the robot, andhuman speech emanates from the robot’s mouth, enabling the user
to act and work freely at the robot’s location while remaining attheir actual location.
Telexistence enables the same state achieved by wearing an
exoskeleton human amplifier (described in the section on motion
augmentation) to be achieved without the user physically going to
the location. Therefore, space augmentation could be considered avirtual exoskeleton human amplifier. However, telexistence issuperior to exoskeleton human amplifiers in two respects—robot
failure poses no danger to the human user, and the robot can be
operated automatically for simple jobs that can be done by the
robot alone.
Creating a microrobot with a telexistence link to a human user
would let the user perform tasks as a virtual miniaturized versionof themselves. For example, applications of this technology could
place robots in normally inaccessible locations such as inside thehuman body, enabling the robots to carry out various types ofdiagnosis and treatment. Since diagnosis and treatment require
human experience and knowledge, it would be very effective toenable medical doctors to use robots with the feeling that theyvirtually enter the human body, where they could makeobservations and assessments, and carry out treatment.
Entertainment applications of the technology could placesurrogate robots shaped as land or marine animals within flocks of
the animals so that the users have experience of playing with theanimals as their mates.
Spatial human augmentation can also be understood in terms of
the advances made in telecommunication devices such as thetelephone. Famous as the inventor of telephone and for the firstsuccessful experimental demonstration of the telephone in Boston
in March 1876, Alexander Graham Bell was a Scottish-born
American who was passionate about education for the deaf andthe dumb and a good adviser to Helen Keller. One of the first
telephone users is said to have felt as though her grandmotherwere present and whispering in her ear. The telephone could beconsidered a telexistence device for sound; hence, “telephone”
was certainly an appropriate choice of name.
More than 135 years after Bell’s invention, the rise of mobile
phones and/or smart phones has now enabled almost everyone toexperience auditory telexistence—the telephone—while walking.
The invention of the telephone was followed by the invention of
television (TV). However, television was not an appropriate
choice of name. TV is a broadcasting device and the successor of
the radio, and not at all the successor of the telephone. Video
phones are the successor of the telephone. They are appearing in
the latest-model mobile phones or smartphones and are starting to
be used worldwide. Teleconferencing systems are also aiming at

visual telexistence. Despite their lack of immersiveness,
applications such as Polycom and Skype are practical andwidespread. However, 3D images can still not be conveyed freely.
Research is underway on telexistence booth systems aiming toenable “mutual telexistence” that realizes life-size 3D face-to-faceconferences among multiple users. Placed in public places, offices,or homes, telexistence booths would convey life-size 3D images
in real-time. Telexistence booths would be similar to public
telephone booths. Each member of a conference would enter atelexistence booth in a public place or office. Once a
communication path had been established, face-to-facecommunication would be possible. Each member would be able tosee the other members’ faces in a simulated conference room in a
VR environment set in common for all the members. They canmove around the room freely, and gestures and other bodylanguage would also be conveyed.
Time-domain human augmentation is also possible.
Telexistence, which enables instantaneous transportation ofhumans between places with a time difference, can be considered
to transcend space and time in a sense. Moreover, the life log
application described previously would record the world of thepast, creating a space/time augmentation that would let the user
return to that past world.
An implementation of telexistence would be to create a recordof the user’s behavior by using telexistence avatar robots that
could be reproduced by a robot at any time. Records of people are
now stored as pictures, photos, sculptures, and videos. It may bepossible to store these records and memories in the form oftelexisting avatar robots. Even after a person passed away, theperson can exist for a long time as the form of his/her telexistence
avatar robot, which has memorized fully his/her behavior andperformances, adding to his/her appearance and voices.
5

5.3 Telexistence Manipulation System: TELESAR
The first prototype telexistence master-slave system for
performing remote manipulation experiments was designed anddeveloped, and a preliminary telexistence evaluation experiment
was conducted [14, 15, 16]. The slave robot employs an
impedance control mechanism for contact tasks. An experimental
block-building operation was successfully conducted using ahumanoid robot called TELESAR (TELExistence Surrogate
Anthropomorphic Robot). Experimental studies of the tracking
tasks quantitatively demonstrated that a human can telexist in aremote environment through a dedicated telexistence master-slave
system (Figure 7) [16].

TELEXISTENCE

5.1 What is Telexistence
Telexistence is a fundamental concept that refers to the generaltechnology that allows a human being to experience a real-time
sensation of being in a place other than his/her actual location andto interact with the remote environment, which may be real,virtual, or a combination of both [5]. It also refers to an advanced
type of teleoperation system that allows an operator at the controls
to perform remote tasks dexterously with the feeling of being in asurrogate robot working in a remote environment. Telexistence inthe real environment through a virtual environment is also
possible.
Sutherland [4] proposed the first head-mounted display system,
which led to the birth of virtual reality in the late 1980s. This wasalmost the same concept as telexistence in computer-generated
virtual environments. However, it did not include the concept oftelexistence in real remote environments.
The concept of providing an operator with a natural sensationof existence in order to facilitate dexterous remote robotic
manipulation tasks was called "telepresence" by Minsky [9] and"telexistence" by Tachi [10]. Telepresence and telexistence arevery similar concepts proposed independently in the USA and inJapan, respectively. However, telepresence does not include
telexistence in virtual environments or telexistence in a realenvironment through a virtual environment.
5.2

Japanese national large scale “Advanced Robot Technology inHazardous Environment” project, which began in 1983, together
with the concept of “Third Generation Robotics.” The theoreticalconsideration and systematic design procedure of telexistence
were established through the project. An experimental hardware
telexistence system was developed and the feasibility of theconcept was demonstrated.
Our first report [11, 12] proposed the principle of a telexistence
sensory display and explicitly defined its design procedure. The
feasibility of a visual display providing a sensation of existence
was demonstrated through psychophysical measurements
performed using an experimental visual telexistence apparatus.
In 1985, a method was also proposed for developing a mobile
telexistence system that can be driven remotely with both auditory
and visual existence sensations. A prototype mobile televehicle
system was constructed and the feasibility of the method wasevaluated [13].

Figure 7: Original TELESAR.

5.3.1 Augmented Telexistence
Telexistence can be divided into two categories: telexistence in areal remote environment which is linked via a robot to the place
where the operator is located, and telexistence in a virtualenvironment which does not actually exist but is created by acomputer. Telexisting in a real remote environment with acomputer-synthesized environment combined or superimposed on
it is referred to as augmented telexistence. Sensor information in
the remote environment is used to construct the synthesizedenvironment.
Augmented telexistence can be used in a variety of situations,such as controlling a slave robot in an environment with poor
visibility. An experimental operation in an environment with poor
visibility was successfully conducted by using TELESAR and its

How Telexistence was Conceptualized andDeveloped

The concept of telexistence was proposed by the author in 1980
[4], and it was the fundamental principle of the eight-year

Figure 8: Virtual Telesar at work.

dual anthropomorphic virtual telexistence robot named Virtual
Telesar (Figure 8) [17, 18].
5.3.2 Telexistence into a Humanoid Biped Robot
Based on the telexistence technology, telexistence into ahumanoid biped robot was realized in 2000 under the “Humanoid
Robot Project” (HRP) [19]. Figure 9 presents the robot
descending stairs. Since the series of real images presented on thevisual display are integrated with the movement of the motion
base, the operator experiences a real-time sense of walking or
stepping up and down. This was the first experiment in the world
which succeeded in controlling a humanoid biped robot by using
telexistence (Figure 9).

Face-to-face communication was also confirmed, as local
participants at the event were able to see the remote participant’s
face and expressions in real time. It was further confirmed that thesystem allowed the remote participant to not only move freely
about the venue by means of the surrogate robot, but also perform
some manipulation tasks such as a handshake and several gestures.
5.4.1

Face-to-Face Telexistence Communication using
TWISTER Booths
The following systems were added to original TWISTER’s
omnidirectional 3D autostereoscopic display: 3D facial image
acquisition system that captures expressions and line of sight, anda user motion acquisition system that captures information aboutarm and hand position and orientation. An integrated system wasconstructed whereby communication takes place via an avatar in a
virtual environment. The results of having two participants engage
in TWISTER-to-TWISTER telecommunication verified thatparticipants can engage in telecommunication in the shared virtualenvironment under mutually equivalent conditions (Figure 12)[23].

Figure 9: Telexistence using HRP Biped Robot.

5.4 Mutual Telexistence: TELESAR II & IV
A method for mutual telexistence based on the projection of realtime images of the operator onto a surrogate robot using
retroreflective projection technology (RPT) was first proposed in
1999, and the feasibility of this concept was demonstrated by theconstruction of experimental mutual telexistence systems using
RPT in 2004 [20]. In 2005, a mutual telexistence master-slave
system called TELESAR II was constructed for the Aichi World
Exposition. Nonverbal communication actions such as gesturesand handshakes could be performed in addition to conventionalverbal communication because a master-slave manipulation robot
was used as the surrogate for a human [21]. Moreover, a person
who remotely visited the surrogate robot’s location could be seen
naturally and simultaneously by several people standing aroundthe surrogate robot (Figure 10).

Figure 10: TELESAR II.

The mobile mutual telexistence system, TELESAR IV, which isequipped with master-slave manipulation capability and an
immersive omnidirectional autostereoscopic 3D display with a
360° field of view know as TWISTER, was developed in 2010[22]. It has a projection of the remote participant’s image on the
robot by RPT (Figure 11).

Figure 11: TELESAR IV.

Figure 12: TWISTER to TWISTER Telexistence.

5.5 Telexistence Avatar: TELESAR V
In telexistence, an operator can feel his/her slave robot as an
expansion of his/her bodily consciousness and has the ability tomove freely and control the slave robot in a similar way to his/herbody movement. In order to certify this concept in telexistence,
the TORSO (TELESAR III) system, which can acquire visual
information in a more natural and comfortable manner by
accurately tracking a person’s head motion with 6 DOF, wasconstructed [24].
TELESAR V, a master-slave robot system for performing fullbody movements including 6-DOF head movement as TORSO,
was developed in 2011 (Figure 13) [25]. In July, 2012, it was
successfully demonstrated that TELESAR V master-slave system
can transmit fine haptic sensation such as texture and temperatureof the material from an avatar robot’s fingers to a human user’s
fingers. The avatar robot is a telexistence anthropomorphic robot
with 53-degree-of-freedom body and limbs and it can alsotransmit visual and auditory sensation of presence to the humanadding to the haptic sensation [26, 27].

Figure 13: TELESAR V.

5.6 Telexistence in the Future
Telexistence technology has a broad range of applications such as
operations in dangerous or poor working conditions withinfactories, plants, or industrial complexes; maintenance inspections
and repairs at atomic power plants; search, repair, and assembly
operations in space or the sea; and search and rescue operations
for victims of disasters and repair and reconstruction efforts in theaftermath. It also has applications in areas of everyday life, suchas garbage collection and scavenging; civil engineering;
agriculture, forestry, and fisheries industries; medicine andwelfare; policing; exploration; leisure; and substitutes for test
pilots and test drivers. These applications of telexistence are
inclined toward the concept of conducting operations as a humanmachine system, whereby a human compensates for features thatare lacking in a robot or machine.
There is also a contrasting perspective on telexistence,
according to which it is used to supplement and extend humanabilities. This approach involves the personal utilization oftelexistence, that is, liberating humans from the bonds of time andspace by using telexistence technology.
6

CONCLUSION

1) The history of 3D elucidates that it has a thirty year cycle ofevolution. Its dawn was in the 1920s, followed by the first 3D
craze in the 1950s, the second 3D craze in the 1980s, and themost recent 3D craze in the 2010s.
2) History of VR has revealed that VR evolves about a decade
after the 3D crazes, i.e., the dawn of VR was in the 1960s, andthe first VR craze was in the 1990s following the first 3D
craze and the second 3D craze, respectively.
3) This leads to the conjecture that the next VR / AR craze will bein the 2020s.
4) AR supplements humans in their senses and intellect, while
human augmentation or AH (augmented human) augments
humans not merely in their senses and intellect but also intheir motions and abilities to transcend time and space.
5) Human augmentation in time and space is called telexistence.
Telexistence frees humans from the constraints of time andspace. It allows them to exist virtually in remote locations, aswell as to interact with remote environments that are real,computer-synthesized, or a combination of both.
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