VR Hand Hygiene Training System That Visualizes
Germs to Be Washed and Removed
Shogo Shimada∗ , Kenji Funahashi∗ , Kenta Ito† , Yoshimi Tanase† and Kumiko Iwazaki‡∗ Department of Computer Science, Nagoya Institute of Technology, Japan† Aichi Children’s Health and Medical Center, Japan‡ Department of International Information Science, Kinjo Gakuin University, Japan

Abstract—Although people should wash their hands to prevent
infection especially in a place where many people gather, such as
in a hospital or a school, it is difficult to teach young children towash their hands properly. The challenge is to make them understand why they should wash their hands even if they are looking
already clean. We propose a novel VR hand washing training
system for preschool and lower school grade of children. Thissystem superimposes germ illustrations on their hands through a
HMD, and germs get removed when children move their hands
in a proper washing motion. Then, they can intuitively learn thereason and the method. We had an experiment to evaluate if
our proposed VR system is more effective than a conventional
hand hygiene instruction for young children. The result of theexperiment will suggest the effectiveness of the proposed system.
Keywords—Virtual Reality,Interactive learning environments

I. I NTRODUCTION
In the field of paediatric medical care, there is a risk ofcontact infection via things such as children’s toys. The easiest
and most effective precaution of contact infection is handhygiene. Hand hygiene awareness is necessary not only inthe epidemic period such as influenza but also on a daily
basis. Currently, hospitals put up a poster and hold a class
How to wash hands for children. On the other hand, many
researches have been conducted to improve the awareness ofhand hygiene such as the development of simulation games [1]or the projection mapping to alcohol bottles for disinfection[2]. These studies are not particularly targeted to children.
In this paper, we propose a novel VR hand washing training
system for preschool and lower school grade of children. First,
the system obtains a position and a posture data of bothuser s hands. It superimposes germ illustrations on user’shands through a HMD, and germs get removed when the user
moves his hands in a proper washing motion such as rubbing
both hands. It is expected that this experience makes children
intuitively learn a proper method to wash their hands and its
importance. A data glove is used to obtain posture of user’s
hand as a VR device. In this research, we use Leap motion
to obtain posture of a hand because of portability and price.
By the way, a hand occluded by the other can not be detected
through recognition based on image such as the Leap motion.
We assume that the hand stays and continues as the previousprocess time, even if one hand is not detected. Then the systemjudges washing motion with typical gestures for each part of

the hand advised by a medical doctor. In Chapter 2, we will
describe specific gestures and judgment method.
II. V R HAND WASHING TRAINING SYSTEM
The areas where the germ illustration is superimposed aspalm, fingertip, back, thumb, interdigit and wrist of both hands
are decided according to the WHO Guidelines[3]. The methodof how to wash each area properly is usually explained
as Table I. By the way, our proposed system obtains the hand
position and posture through Leap Motion. Hand position isgiven by position of wrist, and hand posture is given by relative
position of a joint and fingertip from hand position, normal
vector of a palm plane, and radius of a sphere that fits to acurvature of a hand for grip condition. We decide each gesturefor each washing method using these data. The gestures towash are defined as Fig. 1 to Fig. 6. The current hand positionand posture are judged whether they match each gesture bycomparing the following values with a threshold value.
TABLE IHOW TO WASH EACH AREA PROPERLY

palm
fingertip
interdigit
thumbbackwrist

rub hand palm to palm
rub with clasped fingers of a hand in another palm
palm to palm with fingers interlaced
grasp thumb with another palm and rub
rub back of hand with another handrotating rub of a wrist in another palm

palm
distance: distance between palm of both hands isless than thresholdorientation of palm: horizontal element of palm
normal is greater than thresholdfingertip
distance: distance between washed finger and another palm is less than thresholdorientation of palm: horizontal element of palm
normal is greater than thresholdorientation of finger: horizontal element of orientation of finger is greater than thresholdinterdigit
distance: distance between interdigit of both hands
is less than thresholdorientation of palm: horizontal and vertical elementof palm normal is greater than threshold
thumb
distance: distance between washed thumb and another palm is less than thresholdorientation of palm: depth element of palm normal
is greater than threshold
radius: radius of sphere fitting to hand curvature isless than thresholdbackdistance: distance between palm of both hands isless than thresholdorientation of palm: vertical element of palm normal is greater than threshold

Fig. 3. Gesture of washing a interdigit

wrist
distance: distance between washed wrist and anotherpalm is less than thresholdorientation of palm: vertical element of palm normal is greater than threshold
radius: radius of sphere fitting to hand curvature isless than threshold

Fig. 4. Gesture of washing a thumbFig. 1. Gesture of washing a palm

Fig. 5. Gesture of washing a backFig. 2. Gesture of washing a fingertip

The system checks if the input posture matches with eachgesture at regular intervals. When an occluded hand is not detected through Leap Motion, it is assumed that the hand stays
and continues as the previous process time. The damaged pointof corresponding germ is increased if the posture matcheswith a gesture. The germ gets transparent, then removed
in accordance with an increase of the point. Because thissystem is used by children, it is necessary to show the systeminteresting. The image of hands captured through an infrared

Fig. 6. Gesture of washing a wrist

camera of Leap Motion is processed to skin color, and shown
on a HMD. The germ CG illustrations are also colored, andshown on a HMD. Illustration of a character supporting theFig. 7. Hands and germs displayed on a screen

Fig. 9. Handwash check with black light, good example

hand washing is drawn in the background. In addition, aneffect sound is made when germ is damaged and removed. Thegauges showing time limit and damage points are displayed
like video games. Three result screens are prepared, and oneof them is displayed according to the total damage point at theend of washing. System execution screen through the HMDis shown in Fig.7. You can wash your hands while looking
germs, and recognize the disappearance visually.
III. E XPERIMENT AND RESULT
We had an experiment to evaluate whether our proposed VR
system is more effective than a conventional hand hygiene
instruction for young children. We used monocular vision
HMD to use with mobile phone in consideration of the riskof visual function. Leap Motion was attached on the front ofthe HMD. The mobile phone screen is synchronized to PC
screen with USB cable. The HMD is fixed on the stand as
shown in Fig. 8, because it was too heavy to wear for youngchildren. The subjects were 12 children who were admitted
at the Aichi Children’s Health and Medical Center. First, anurse and a childcare-giver taught 5 children how to wash theirhands using a illustration and oral instruction, then checked theareas of their hand using fluorescent paint and black light. If
the hand is rubbing tightly, the fluorescent paint spreads inthe hand, then it becomes white (Fig. 9). If the hand is notrubbing, the fluorescent paint does not spread, so the back of

Fig. 10. Handwash check with black light, bad example

the right hand is not white (Fig. 10). The other 7 children
learned how to wash their hands using proposed system, itmeans, tried to remove germs by rubbing their hands, then they
were also checked as a same way. We gave 2 points if childcould wash interdigit, thumb and wrist respectively, thanks topreventionist’s advice that it is usually difficult to wash thoseareas. The other three areas were given 1 point. This test wasin 9 points. The average points of Table II and III suggestthat our proposed system was better than conventional oral
explanation, especially on the difficult areas. We published apress release, and held a demonstration event. Five outpatientsused this system (Fig. 11), then they and their parents gave
positive opinions.
TABLE IIR ESULT FOR CONVENTIONAL INSTRUCTION

Fig. 8. Experiment scene

age/sex

7/F

11/M

6/M

3/F

5/M

ave.

palmfingertipbackinterdigit
thumbwrist

11122011122011122011
1000

1
10222

110.8
1.6
1.60.4

total

775386

TABLE III
R ESULT FOR PROPOSED VR SYSTEM
age/sex

11/F

6/F

10/F

6/M

6/F

7/M

11/M

ave.

palm
fingertipbackinterdigit
thumb
wrist

1
102
20

1
1
12
20

1
1
1
200

1
1
1222

1
10222

100
2
02

11
12
20

10.86
0.57
2
1.43
0.86

total

67

598

57

6.7

Fig. 11. Demonstration scene

IV. C ONCLUSION
In this research, we proposed VR hand washing training
system for preschool and lower grade of school children inorder to improve the hygienic environment in pediatric medicalcare. In the future, we would like to put our system to practicaluse at an outpatient section, a preschool, and a school for smallchildren. We also would like to analyse data of use of this,then improve hand recognition and its correction, judgement
method to wash, and a way to show for children.
ACKNOWLEDGMENT
The authors would like to thank our colleagues. This work
was cooperated in part by NTT DOCOMO, INC.
R EFERENCES[1] M. Vazquez-Vazquez, V. Santana-Lopez and M. Skodova, Hand Hygiene
Training through a Serious Game: New Ways of Improving Safe Practices,
Serious Games and Applications for Health (SeGAH), 2011[2] Akinori Kanazawa, Toshiko Asai and Akinori Minazuki, Constructionof a MR Space using Projection Mapping to Promote Hand Hygiene,
Advanced Applied Informatics (IIAIAAI), 59, 2014, pp. 247-252[3] WHO, WHO Guidelines on Hand Hygiene in Health Care: a Summary,
2009, pp. 14