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Panoramic Audio and Video: towards an
Immersive Learning experience
Alfonso TORREJON, Prof. Vic CALLAGHAN and Prof. Hani HAGRAS
Intelligent Environments Group, Department of Computer Science and Electronic
Engineering, University of Essex, UK
{atorree, vic, hani} @ essex.ac.uk
Abstract. Historically, learning has been seen as part of the human process to
achieve a status, income and a better future. Traditionally students travel to attend
lectures or participate in brainstorming and training sessions benefiting from the
interaction afforded by the physical learning environment, the classroom, and the
wider University facilities. However, financial pressures arising from national and
global competition are putting pressure on Universities to find more cost-effective
ways of delivering education. While distant learning has been always there, it is
clear that this approach needs substantial improvements in order to deliver a
similar learning experience to physically attending a university. To these end, this
paper presents a novel immersive telepresence system that allows remote or distant
students to customize their virtual presence at seminars and lectures based on a
360° panoramic video projected onto a 180° curved projected screen (an
immersive shell). Audio is also collected with 3D information in order to be
reproduced more naturally at the remote location. The arrangement is intended to
provide online learners with a more faithful replication of human perception, akin
to what they would experience in a real learning environment. Technically, to do
this we use a 360° mirror to capture the lecture room scene and transmit it to
remote locations where it is reconstructed the original image from spherical to
Cartesian coordinates providing a novel but natural immersive experience. This
paper describes the motivation, model, computational architecture and our main
findings.
Keywords. Telepresence, Immersive environment, Panoramic audio, Panoramic
video.
Introduction
Financial pressure are putting pressures on Universities to look for more cost-effective
ways to deliver education.. At the same time there is a new generation of students that
are more comfortable with online systems which, together with advances in online
technology has driven our motivation for this work.
Beyond education, another market and technology driver is the gaming industry
which seems to grow at an exponential rate. As a result, numerous educationalists are
looking at games technology to understand the core of values that attract users, so the
ideas could be applied to education. Having studies these areas, in this paper we
propose a new model combining traditional teaching methods with immersive media,
taking advantage of the gaming interfaces and workflow to produce an effective
interaction between remote and local attendees.
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The term “Telepresence” was coined back to 1980 by Marvin Minsky, a
Massachusetts Institute of Technology professor, who described it as “the ability to
present and manipulate objects in the real world through remote access technology”
[1]. Later the term has come to refer to remote manipulation paired with a high quality
sensory feedback where the end-user “perceives” the remote space as “local” in order
to perform the task more effectively.
Following this definition, Bill Buxton redefined Telepresence to include
telecommunication, as “telepresence is the use of technology to establish a sense of
shared presence or shared space among geographically separated members of a
group” [2], where presence is considered in terms of two spaces: that of the person and
that of the task.
Traditional videoconferencing is a good attempt to establish this shared personal
space. However, as technology advances, videoconferencing is increasingly focusing
on achieving the sensory feeling of “being there”.
Towards those ends we have created an immersive telepresence system that
facilitates physically dispersed students, or groups, to collaborate around a shared task
with a sense of shared presence. At one end of the link, the local space (e.g. a lecture
theatre), a 360° mirror lens is placed in the room, from where a spherical image is
captured and then transmitted to a remote location in real time. Once this stream is
delivered, it is converted from polar to Cartesian coordinates to create a panoramic
video that is projected onto a 180° screen. 3D audio is also collected in order to
reconstruct a more natural sound image at the remote learner end by using binaural
techniques and directional speakers or headphones.
This setup allows remote viewers to participate in events as though they were
local participants, enjoying much greater control over their visual and audio context.
This work was inspired by other immersive projects such as the “Mixed
Reality Teaching and Learning Environment” (MiRTLE), an Open Wonderland
platform [3] which uses virtual reality in the form of avatars to bring geographically
dispersed learners together [4]. The work described in this paper advances this field in
two important respects; first it replaces avatars with video of real people and secondly
it collects panoramic audio at 2 different levels; one for pure audio transmission to the
remote user, and a second to calculate the dimensional position of the source, thereby
enabling the audio to be recreated and spatially controlled by the end user.
1. Distance learning
Distance learning in its most basic form (e.g. sending materials by post) has been
around for more than a century. While traditionally it has been accepted as a method to
get on to the education ladder when resources such as time, money and commitment
are not fully available nowadays, in addition, it is evolving as a way to provide an
extra-curriculum option for people with busy lives . Some Universities have found that
distant delivery of lectures has allowed them to have multiple campuses on different
locations. This enables them to project their cultural and academic values to other
cities, countries and even continents or societies, making better use of their best
resources, their individuals, and at a lower cost. Other Universities have used online
learning to massively expand their student numbers, for example Shanghai Jiao Tong in
China has 40,000 distant learners taking the same examinations as those in their real
campus [4].
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Some of the issues in the past, with relation to distant learning, has been addressing the
quality of the educational experience as compared to that experienced by students in
traditional programs. It has been found that the format of delivering the content has
little effect on student achievement, as long as the technology is appropriate for the
content and all participants have access to the same technology and resources. [5]. The
use of online content has been extended from remote learners to local students who
want to review a lecture that has ended. Digital lecture recording and capturing has
flourished in recent years.
Recent statistics from the High Education Statistic Agency (HESA) [6] have
shown that over 10% of the students enrolled at UK Universities during 2010-2011
were studying through distance learning, while another 10% undertook some kind of
distance module during their university studies. All of them have used some remote
presence tools for collaborative work, such as Skype®, Facebook® groups, Moodle®
forum, course message boards, YouTube® videos and similar tools.
Traditional method for distance learning originally involved sending books, tests
and videos by post to registered students but have now been replaced by more modern
methods. For example, some institutions created their own radio and TV programs to
support learning. Videos were introduced and later the internet, the largest repository of
learning material to-date. Some Universities have produced a number of courses with
more up-to-date resources such as screen capture, RSS audio recording, web pages
often centralising learning resources, via systems such as Moodle®, offering message
boards and resources available 24/7 to suite the student needs. Social tools such as
Tweeter®, Facebook®, YouTube®, Second Life®, etc, have also been added by many
universities as part of the student experience, communication and marketing.
2. Social Interaction and Social Presence
What make students engage in an online learning? Beyond the chosen subject itself
there is a social view that emerges in support of online learning as the individual join a
community group [7][8]. There are 3 interrelated elements that have to be considered:
A. Social Presence
Social presence is defined as the degree to which the student feel socially and
emotionally connected to others in the group, projecting themselves as “real” people,
independent of the communication medium used [9][10], and should extend beyond
geographic boundaries to allow the remote individual to belong to the group [11].
Socio-cognitive theorists describe learning as an interactive group process in which
learners actively construct knowledge and then build upon that knowledge through the
exchange of ideas with others [12].
Studies on social presence [13][14]determined that social presence was
composed of three subjective elements: co-presence, intimacy, and immediacy. None
of them naturally available at distance learning, so the need to build a model that takes
those into consideration is a paramount for the success of any distant education
program. In this “value social interaction“ and ”learning interaction” are the key factors
needed to achieve learner satisfaction and goal achievement, which is basically the
final goal of any teaching institution.
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B. Cognitive Presence
Describes the extent to which the student is able to construct meaning through
sustained communication, reflection and discourse or, as Garrison defined:”The
exploration, construction, resolution and confirmation of understanding through
collaboration and reflection in a community of inquiry” [15].
C. Teaching Presence
The glue element to bring all these together is the teaching presence, by designing,
facilitating and providing direction to cognitive and social presence, thereby allowing
students to achieve their full potentials. In this way the educator is responsible for
providing emotional presence that will lure and engage the student into being
inquisitive in order to better progress [16].
2.1. Emotions
Emotions are universal phenomena that people experience in everyday events
throughout their lives, and obviously are present in online learning communities [16].
Online objects, such as emoticons, have been created in order to communicate
emotions while socialising online [17]. Research on emotional presence within online
communities demonstrates the salience of emotion in online learning. Thus, as Harasim
stated “emotion must be considered, if not a central factor, at least as a ubiquitous,
influential part of learning” [18].
Interaction in any traditional classroom is far more complex than the
interaction that occurs in any online course. While the two instructional environments
are different, the main asset in a traditional classroom is the pedagogical value of
synchronous interactive communication. The student “feels” part of the process and the
event, not as external observer but at the pedagogical core. The importance of
interaction in distance education has been acknowledged and researched [19][20]. In a
traditional classroom the lecture and the scenario will provide visual cues that the
student will add into the learning process to reinforce their experience. Because the
lack of this connection, remote students may fall into the feeling of isolation and lack
of connection toward the lecturer and fellow students. Thurmond et al. reported that
students who responded more positively to knowing their instructors also tended to
believe that there were a variety of ways to assess their learning, reporting more timely
feedback from the instructor; and participating more actively in course discussions
[21]. Their research also found that students were more satisfied with their courses and
reported greater learning when more of their course grading was based on participating
in live discussions [22] and they believed that their participation in discussions
enhanced their learning. These findings revealed a positive relationship between high
levels of group activity in the courses and their learning. But how is it possible to use
distance learning technology to promote discussion with remote students and to
engender timely feedback?
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3. Sense of Community
In a seminal 1986 study, McMillan and Chavis [23] sought to describe a sense of
community and offered four criteria necessary for an acceptable definition. Their model
to define sense of community applies equally to both place-based and non-place-based
communities, and their elements equally apply. Membership is concerned with
boundary issues, often represented by feelings of belonging to or sharing something in
special. Influence looks at an individual’s sense of mattering, being shaped by the
group, and able to make a difference. Needs, more specifically the integration and
fulfillment of needs, deals with reinforcement and distribution of common resources.
Emotional connection speaks to a community’s shared history, similar
experiences, and common world-view. The ability to identify other members of the
community allows people to determine how to spend resources and time and with
whom they feel comfortable. The feeling that the individual can influence or add value
to a group will increase the social value, in a bidirectional way. In order to be attracted
to the group, an individual must have the potential of influencing the group otherwise
he will see it as a burden. The individual association must be rewarding to members
and successes relating to the group should bring them closer together.
In conclusion, a group of people with shared values and membership, with
similar goals and priorities, will be easily able to focus on specific tasks in a consistent
and mutually beneficial way. Sharing emotional events is crucial in creating sense of
connection between those members, and in order to provide this emotional connection
there is a requirement for some kind of direct interaction between them, based around
common task and goals.
It is also evident that people who expend time and energy on projects will feel
more emotionally involved in the outcome than those that don’t. In addition, providing
support, identity and emotional connection can offer the attraction needed for people to
progress towards their personal goals.
4. Gaming applied to Learning
Games illustrate the importance of the points made in the preceding section. In multi-
participant online games, individuals are given a task, shared with other members in
two ways, one as contender to achieve the best individual score and a second as a
collaborator helping a team to achieve its goal.
Research has shown that Multiplayer Online Games (or Massively
Multiplayer Online Role-Playing Games - MMORPG), like ‘World of Warcraft’,
teaches online players very important life skills such as teambuilding, communication
and leadership. Those skills can be combined and be extended to more traditional
learning subjects such as economics, sociology, math and science, taking advantage of
the learning culture created around MMORP [24].
According to Slater [25] an Interactive Animated Pedagogical Agent consists
of Adaptation, Motivation, Engagement and Evolvement. The two first agents are
easily understood:
A. Adaptation: evaluates the learner’s understanding throughout the interaction, adapts the
lesson plan accordingly. It also ensures a learner has a good understanding of the
basics before progressing to more sophisticated concepts
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B. Motivation: this prompts students to interact by asking questions, offering
encouragement and providing feedback;
But how can teachers engage and evolve with distant learners through the course
of a lesson? Games create engagement, which is one of the cornerstones of any positive
learning experience. According to Karl M. Kapp, a learning expert, game-based
mechanisms can help to create a meaningful learning experience [26]. The paper we
cite [26] shows how to create and design games that are effective and meaningful for
learners. Gamification is the use of game thinking and mechanism to engage audiences
and solve problems. This term comes from the videogame industry and the
development of the internet. Zicherman [27] introduce the concept of a flow zone and
illustrate a boredom area to where the player loses interest, and the anxiety area, where
the player will probably shutdown the system.
Inspired by Self-Determination Theory (SDT), Deci et al [28] determined that
the more control someone has in choosing what to do, the better the chance the person
will be internally motivated to do it. People who want to do something because it is fun
are more likely to succeed with their intentions than those who are doing something for
a reward or to "learn something." When someone is taken into a playful space then the
flow of learning will come naturally, with disregard of age, background or any other
characteristic. Many of those examples in real-world include museums, libraries, zoos,
and botanical gardens [29]. Many of these leisure’s settings employ game elements to
help users find personal connections with the non-game setting and their cultural value
behind the scene. The phrase "Ludic learning space" was coined by Kolb and Kolb to
define a space where play is used to help someone explore and learn about a topic or, to
use his words; “free and safe space that provides the opportunity for individuals to play
with their potentials and ultimately commit themselves to learn, develop, and grow"
[30]. Those spaces are designed in such way that individuals can choose to enter,
“leave themself behind” and engage in play. In conclusion, if opportunities are created
then individuals will explore the given space, discover that is meaningful to them and
then engage, reflect, participate and allow themselves to be transformed by the system
[31].
5. Panoramic Model for Telepresence
The concepts described in the preceding sections led us to design a novel 360°
panoramic video and audio telepresence system. We took on board the findings of
earlier research that the environment should be as close to a real classroom as possible
and that the participants should feed social and emotionally engage, and in control.
We therefor specified and built the system described in the proceeding
sections. Using this system we gave gathered measurements and recommendations in
which we present in this paper. We have solicited a number of healthy subjects without
visual or auditory impairment to assist us in this experimental work. It is important to
remember that this project does not aim to provide a 3D image that can deceive the
brain into a false belief of contextual presence [4] but rather to provide a 3D immersive
experience where the users can directly manipulate the direction of view and its field of
view without affecting others’ field of view (FOV).
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5.1. Human Stereoscopic Field of View
5.1.1. Horizontal Field of View
For most people, the central field of vision, where both eyes observe an object
simultaneously, covers an angle between 50° to 60°, depending the visual ability of the
individual. This area is called “binocular field” and any object within this field
provides a sharp representation, with a precise depth perception where colour and
spatial discrimination is possible. Any work on visual reconstruction, to present an item
as “real”, needs to be focussed within this area. There is a 30° preferred angle (15° per
eye from the centre of the axis), and a 70° of immediate field of view (35° per eye).
Outside those angles our peripheral vision resides, where the information
collected is treated in a different manner but may be as important as the central one.
Although our peripheral vision is not as good as central for performing detailed work,
but it is especially important and good at detecting motion and pre-fetching tasks [32].
A very small eye movement can provide a large set of new data on the horizontal
axis, up to 200°. See Figure 2.
Figure 1. Horizontal Field of View. Figure 2. Horizontal field of view and head rotation.
5.1.2. Vertical Field of View
In relation with the vertical field of view, people have developed a different way of
perceiving the surrounding space, probably more related to walking and hunting
activities. The upper limit is 50° from the normal line of sight, while it is 70° from the
same axis for the lower area. It differs if the subject is seated or standing by up to 5° at
the preferred viewing area, and same for the area where colour, space and shapes can
be discriminated, amounting to 55° in total [33]. See Figure 3 for more information.
Figure 3. Vertical Field of View.
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For optimal viewing on any projected image, the field of view should be
larger than 36° per eye, a total FOV of 72°, with an upper bound of 70°, a total FOV of
140° including the peripheral vision, before the viewer begins to feel uncomfortable
and will be induced to nausea and disorientation.
6. Proposed System Architecture
6.1. Spatial Video Capturing and Reconstruction
Images are collected from the main location (where the event takes place), such as
lecture or seminar room, via a spherical mirror setup in the middle of the room, at a
specific height to emulate a seated subject attending the event. This is a 360° mirror
supported on a tripod, and with a webcam pointing down toward the center of the
mirror. The resulting image is a polar coordinated image (Figure 4 and 5).
Figure 4. Spherical mirror and camera in room setup. Figure 5. Polar image transmitted
This image is captured by the local Flash® application embedded into the website
responsible for broadcasting the event, before being transmitted via the internet using a
Media Server, using the RTMP protocol.
At the remote end (e.g. a solitary student) the image is received through a standard
web browser using a Flash® application embedded into a webpage for portability
reasons. This remote application performs the image conversion from polar to
Cartesian coordinates, and then presents it to the end-user as a 360° panoramic real-
time video where the user can use the mouse to move the visibility window left or
right to meet their own needs. We provide a system called ‘Camera Mouse’ to allow
hands-free mouse control, via a camera pointing toward the user’s face and recognizing
any intention of movement.
Figure 6. Polar to Cartesian conversion
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Once the image is converted at the receiving end, it is projected onto a specially
manufactured 180° screen “immersive shell” (Figure 7), produced by Immersive
Displays UK and named ImmersaVu®. This immersive shell is adaptive, and can be set
to different heights to accommodate events that need standing or seating for greater
realism. Distant students at home can use their standard web browser and screens.
Figure 7. Immersive shell
6.2. Spatial Audio Capturing and Reconstruction
The audio is collected through an anechoic mono microphone and transmitted along
with the video signal.
At the same time 3 other micro systems, made of a single board computers,
with an USB microphone attached to each, stream the signal onto the internet, together
with a spatial reference in relation to the panoramic video. Therefore a 3D map of the
audio source location can be reproduced. These 3 systems are located equidistant from
each other to facilitate triangulation. See Figure 8.
Figure 8. Audio triangulation Figure 9. Audio capturing system – Mic 3
These microsystems are Raspberry Pi® devices driving a Samson® USB
microphone chosen for its high gain and quality. The audio source location stream is
transmitted by using ffmpeg® engine producing 3 different streams, one per
microsystem. If more precise location algorithm is needed then a number of
microsystems can be added to the overall system. The main audio, used during
reproduction, is sent together with the RMTP video signal, through the Media Server.
For the audio reconstruction, the end-user receives the audio file as standard
audio, with the RMTP video signal, through the Flash® application. This signal is
combined with an Impulse Response from a HRTF database (Head-Related Transfer
Function) . With the IR of the original room so the end-user is able, by convolution
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reverb, to reconstruct the original sound into a binaural output from a mono anechoic
audio stream.
The values for the HRTF database are provided for each 5° angle of the 360°
location. So every time an end-user drags and drops a panoramic video 5°, either to the
left or to the right, then a new binaural output will be played [34].
Figure 10. Convolution and output signal
Once the audio signal has been convolved with the related IR (Figure 10), it is then
played either though the directional loudspeakers or by headphones. We have used a
HHS-3000 Hypersonic directional loudspeakers® for this setup. These directional
loudspeakers point directly to where the subject’s head should be located.
For binaural reproduction, a set of standard loudspeakers won’t work due to the
nature of the binaural audio that needs precise ITDs (inter-aural time differences) and
ILDs (inter-aural level differences). Because loudspeaker-crosstalk from conventional
stereo loudspeakers interferes with binaural reproduction, either a set of headphones are
required, or a specific and complex crosstalk cancellation system is needed. In this case
we have found that hypersonic directional speakers deliver the narrow beam of audio
required to avoid crosstalk, which provides a similar level of performance to
headphones [35].
7. Evaluation
The system has been evaluated at different intervals with different users, in an ongoing
process when new versions have been created plus it has been presented in numerous
demonstrations. Feedback from those people has been gathered and incorporated into
the project.
From a technical viewpoint, the system can be regarded as being composed of
two distinct sides; the collection and transmission of local video and audio, and the
reception and reconstruction at the remote end. A very important strength of the system
is that it has flexibility built-in as one of the requirements, allowing users to interact in
multiple ways and thereby providing the ability for it to evolve as new technologies
emerge. Adobe Flash® ActionScript 3 (AS3) is used as the current platform because of
its portability and ability to support rapid prototyping but, in the future, any other
platform, such as Java could be used. There are some limitations with AS3 and its
library that could be overcome by Java and need to be researched in future work. The
process of video reconstruction is a memory and processor intensive task and so we
have added elements to the transmission interface in order to regulate quality vs. speed
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during transmission, but need to conduct further investigation to avoid unwanted
pixilation and distortions. Also, further work is needed to perform workbench tests to
confirm if Bitmap Data handling should take place on the server side, instead of the
client.
From a user viewpoint while we have yet to undertake a formal user
evaluation, we have through the development of the system involved users. A, common
view of all those who have experienced the system is that it opens a new range of
possibilities, not just for remote lone learners but also for local classroom based users.
Part of this feedback has led to the development of a browser-only version for
those people accessing the system without an immersive shell. Now that we have
completed the technical work on the platform, we plan to conduct a more formal user-
study but in the meantime, we hope these less formal insights prove helpful.
8. Conclusions
For any distant learning model to succeed is necessary to consider the needs of the
individual and the relation with their environment and group; that is y the way that they
perceive it. When modeling a group, a priority is to allocate a space where the learners
can grow and fulfill their intentions. Being part of a group is an important key to
improving the relationship between the distant learner, the teacher and other peers. The
success of each participant will be manifested in the success of the group.
We have presented a model, based on panoramic immersive media system, capable
of deconstructing and reconstructing remote spaces to give access and additional
information to distant learners and local groups. This model provides key elements for
the success of online activities such as learning, by providing communication and
engagement, and creating a ludic space that is not limited to the academic activity but
to any life learning scenario. Thus, we hope that this work provides a new perspective
for online education that go beyond the current state of the art by offering panoramic
real-time video and audio connections that are controllable and more engaging to users.
Acknowledgements: We are pleased to acknowledge the support of Immersive
Displays Ltd for the ImmersaVU (shell) and Essex University for supporting the
studies of Alfonso Torrejon.
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