Between Real-World and Virtual Agents:
7he Disembodied Robot
Thibault Voisin

Hirotaka Osawa

Keio University
3-14-1 Hiyoshi, Kohoku-ku
Yokohama, Japan

Japan Science andTechnology Agency
4-1-8, Honcho
Kawaguchi, Japantibo@ayu.ics.keio.ac.jp
Seiji Yamada

osawa@nii.ac.jp
Michita Imai

2-1-2 Hitotsubashi,
Chiyoda-ku
Tokyo, Japan

Keio University
3-14-1 Hiyoshi, Kohoku-ku
Yokohama, Japanseiji@nii.ac.jp

michita@ayu.ics.keio.ac.jp

ABSTRACTIn this study, we propose a disembodied real-world agent
and the study of the influence of this disembodiment on
the social separation between the user and the agent. Inorder to give a clue to the user about the presence of therobot and to make possible a visual feedback, we decide
to use independent robotic body parts that mimic humanhands and eyes. This robot is also able to share real-worldspace with the user, and react to his presence, through 3d
detection and oral communication. Thus, we can obtain anagent with an important presence while keeping good space
efficiency, and as a result ban any existing social barrier.

Categories and Subject Descriptors
Figure 1: The Disembodied Real-World Agent

I.2.9 [Robotics]: Operator Interface

General Terms

These studies clearly showed the advantage of embodied
robots, that the physical embodiment enforced the social
presence of the robot, and that the effects of physical embodiment could become highly positive when users are able
to fully interact with the agent by touching it. However,those real-world agents are not widely used either though,because of their generally high space occupancy, leading toa high spatial cost.
In this paper, we thus present a disembodied agent in thereal world, as shown in figure 1, and propose to study theinfluence of the disembodiment of a real-world agent on its
social presence. The agent we consider here consists in bodyparts that mimic human hands and eyes, in order to give tothe user a visual feedback, and is able to react to humancontact through 3d detection, thus giving the possibility forthe user to interact through touching with the agent.
On the other hand, we allow the user to define the contours of the agent’s virtual body: this space will be considered by the agent as being its body. By defining this space,
we thus keep the advantage of having a body, while keeping
a low spatial cost.
This system has the advantages of real-world robots andvirtual agents, thus guarantying a high social presence without sacrificing to the space efficiency.

DesignKeywords
Human-Agent Interaction, Disembodiment, Social Presence,
Real-World Agent, Virtual Agent1.

INTRODUCTION

Real-world agents like robots are able to create a social
interaction thanks to their body presence and ability to perceive user’s actions, when compared to the virtual screen
agents. For example, Wainer et al. [8] proposed to study
the differences in the perception by the user between virtualand real-world agents. As a matter of facts, the users enjoyed the most embodied agents, and considered them as theones that were ’watching them the most closely’. A second
study, proposed by Lee et al. [6], enforced these results, butshowed also that physical embodiment without touch-input
capability causes negative effects.
Copyright is held by the author/owner(s).
HRI’11, March 6–9, 2011, Lausanne, Switzerland.
ACM 978-1-4503-0561-7/11/03.

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2.

MODEL’body’: the agent will react differently depending on theposition of the user’s hand relatively to its body. The possibilities to scratch and pat the agent’s body particularly
enforce its social presence as perceived by the user.

In order for the user to get a visual feedback from the disembodied robot, we decided to use the anthropomorphizedvirtual body parts [7]. These body parts will perform moves
in answer to the user’s behaviors: the eyes follow the user’s
hand, and the arms will move accordingly, as a real-worldagent would do. An oral feedback will also be performed.
To recall to the user the presence of the agent in the realworld, we give to him the possibility to interact with the’body’ of the agent : the user will be able to define the contours of this body in the initialization phase, and to modify
it later if he desires, simply by ’pushing’ on the agent’s body.
To reinforce this presence, we chose to define two different
spaces: ’inside’ and ’outside’ the agent’s body. These definitions will be used to determine object’s position relatively
to the agent’s body, and will enforce the social presence of
the agent as perceived by the user.

3.

4.

During the initialization phase, the agent was able to perceive the user’s hand position and set the actual body limit
in .8s. This response time is close enough to a human reaction time (between .1s and .4s) [4] to obtain a feeling of
spontaneity from the agent. The agent’s body resizing suffers also a light 1.2s delay between the end of the user’s moveand the end of the resizing, which is necessary in order tobe sure that this position is the one chosen by the user.

5.

IMPLEMENTATION

Synchronization of the cameras

The detection of the hand of the user is based on the useof two cameras: a SwissRanger SR4000 [3] for the 3d acquisition and a Logitech C910 [1] for the hand’s recognition. Itwas in that case necessary to use two cameras, because the3d camera acquisition is carried out in gray levels, and its
resolution was too limited to perform precise hand detection. From the position of the hand on the color camera, wedetermine the one on the 3d camera, in order to associate adepth to characteristic dots of the hand (top of the fingers,and palm). The synchronization of the cameras is realized
thanks to the chessboard calibration provided by OpenCV.

3.1.1

6.

ACKNOWLEDGEMENT

This work was supported in part by Grant in Aid for theGlobal Center of Excellence Program for ”Center for Education and Research of Symbiotic, Sage and Secure System
Design from the Ministry of Education, Culture, Sport, andTechnology in Japan”.
The second author is supported by PRESTO JST.

Hand Detection

To perform the detection of user’s hand thanks to the colorcamera, we use in a first time skin color detection, based on
the study of Chai et al. [5] to extract the skin color pixels ofthe image. We then apply a contour detection on the result,and retrieve the contour with the biggest area, from which
we retrieve all convexity defects, in order to determine thenumber of displayed fingers. This feature will then be use forthe interactions with the agent’s body, like the initializationof its body, or its resizing.

3.1.2

CONLUSION AND FUTURE WORKSIn this study, we thus proposed to develop a disembodiedagent. It possesses both advantages from real-world agentsand virtual ones, gaining space efficiency without losing insocial presence.
The next step is now to conduct an experiment to analyze
the differences in the user’s perception between this disembodied agent, real-world and virtual ones. Also, additionalfeatures are still to be implemented, like the understandingof the user’s oral commands, and the detection of objects
non-equipped with localization sensors. Another improvement could be performed by replacing the couple of camerasby a Kinect device: it would thus avoid the synchronization
process, and lead to a gain in the accuracy of the measurements.

The implementation of this project is mainly based on
different parallel data analysis: the detection of the hand of
the user, the answer to user’s commands, and the treatmentof these different data in order for the agent to decide which
action to perform.

3.1

EVALUATION

7.

REFERENCES[1] Logitech hd pro webcam c910. http://www.logitech.com/.
[2] Seeingmachines faceapi.
http://www.seeingmachines.com/product/faceapi/.
[3] Swiss ranger sr4000.
http://www.mesa-imaging.ch/prodview4k.php.
[4] S. D. Card, T. P. Moran, and A. Newell. The Psychology ofHuman-Computer Interaction. Lawrence Erlbaum Associates,
1983.
[5] D. Chai and K. N. Ngan. Face segmentation using skin-color
map in videophone applications. IEEE Trans. Circuits andSystems for Video Technology, 9(4):551, June 1999.
[6] K.M. Lee, Y. Jung, J. Kim, and S.R. Kim. Are physicallyembodied social agents better than disembodied social agents?:
The effects of physical embodiment, tactile interaction, andpeople’s loneliness in human-robot interaction. International
Journal of Man-Machine Studies, 64(10):962–973, 2006.
[7] H. Osawa, J. Mukai, and M. Imai. Anthropomorphization
framework for human-object communication. JACIII,
11(8):1007–1014, 2007.
[8] J. Wainer, D. J. Feil-Seifer, D. A. Shell, and M. J. Mataric.
The role of physical embodiment in human-robot interaction.
IEEE International Symposium on Robot and Human
Interactive Communication, pages 117–122, 2006.

Running Phase

In order to determine the actions the user wants to perform, and how to interpret his moves, the agent needs some
additional information. This data are provided through keyboard input now, but will be replaced by oral commands inthe future, in order to ease the communication with theagent. The agent can actually understand short sentences,
as to trigger the initialization, to resize its body, or to get
information about an element added to its body. The robot
is also able to follow the face of the user, interpret his expression and react accordingly, through the use of the faceAPI
library [2].
At any time, since the agent’s body is defined, the user
is able to interact directly with the agent by touching its

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