Download A Low Cost Approach to Pediatric Pedestrian Safety in Virtual Reality

2009 Third Asia International Conference on Modelling & Simulation
A Low Cost Approach to Pediatric Pedestrian Safety in Virtual Reality
Kuldeep Pandey, Gary J. Grimes
Department of Electrical & Computer Engineering
University of Alabama at Birmingham
[email protected], [email protected]
report of the Fatality Analysis Reporting System
(FARS) of the National Highway Traffic Safety
Administration (NHTSA) showed that at least 308
counties in the USA were at or above the 90th
percentile for child mortality due to road accidents.
This provides a good foundation for pediatric
pedestrian safety research and the need to pursue VR
technology as an economical and practical option [2,
3].
Abstract
Virtual reality (VR) technology has shown
tremendous advancements in recent times. Several VR
tools have been developed which depict advanced
virtual environments that allow user interaction and
manipulation. These tools have found many
applications in training and learning. A VR tool is
proposed in this paper to study the behavior of
children when they are faced with real-world
situations of road safety. The driver for this study is the
fact that pedestrian injuries are a major cause of death
among children ages 5-9 in the United States. The
proposed VR tool includes VR software and hardware
to simulate a virtual environment faced by a typical
pedestrian while crossing the street(s). The VR tool
represents a street with simulated traffic patterns and
an avatar to represent the pedestrian. It is aimed at
training children on safely crossing the roads in order
to avoid accidents. The virtual environment will allow
users to engage in (and investigators to measure)
street-crossing behavior in a controlled environment.
2. Theoretical Framework
VR technology can provide a basis for developing a
tool for teaching children to crossing streets safely [4].
2.1. VR Software
VR technology relies heavily on the computing
resources available in the form of hardware as well as
software. The software needed includes modeling
tools, Application Program Interface (API), and
drivers/engines [4].
2.2. VR Hardware
1. Introduction
VR has always been associated with unique and
expensive hardware. Developments in technology have
brought reductions in cost, and there are a number of
different VR hardware devices available on the market
today. Some popular VR hardware includes Head
Mounted Displays (HMD), Computer Aided Virtual
Environment (CAVE), and Virtual glove [4].
Virtual reality (VR) has developed as a science and
matured as a technology in the last several decades.
Technological advancements in hardware and software
over the years have considerably lowered the cost of
this technology. Such rapid developments have made
VR a high potential field available to a greater number
of application. The use of the computer as a tool for
interactive 3D simulation is highly applicable in almost
every field. Defense, automobile, and avionics
industries have benefited heavily from VR in recent
times, but gradually many other industries have started
implementing VR [1].
2.3. VR Environments
The virtual environment is an extremely important
part of a VR system. Real-world objects, entities, and
scenes are represented as realistic visuals. The virtual
environments provide a foundation for the immersion
or augmentation necessary for a VR system. These
This paper looks at the application of VR
technology in pediatric pedestrian safety. The annual
978-0-7695-3648-4/09 $25.00 © 2009 IEEE
DOI 10.1109/AMS.2009.34
David C. Schwebel
Department of Psychology
University of Alabama at Birmingham
[email protected]
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virtual environments can be two-dimensional or threedimensional depending on the applications [5].
The location is important because if it can be
identified by a physical address, the user will find it
more comfortable to associate with [7]. Relevance is
the first factor of the REAL design methodology. The
author visited several locations in and around the city
of Birmingham, AL. Several surveys were conducted,
and photographs were taken to evaluate and select an
ideal location. However, for the purpose of this study,
a fictitious location was visualized and designed.
2.4. Theoretical Model
The model is explained based on Figure 1. The
subject S is introduced to a VR environment. The VR
environment provides audio and video immersion to
the subject. Based on the audio and video feedback to
the subject, the subject decides to cross or not to cross
the virtual street. The decision from the subject is the
input to the Sensor Pad. Output from the sensor pad is
provided to the animation driver in the VR
environment. If there is no collision between the avatar
and one or more automobile, the process is a success.
If a collision between the avatar and automobile is
detected, the attempt is a failure and a corresponding
output is provided to the subject.
3.2. Selection of the 3D Modeling Software
The selection of a suitable 3D modeling software
was one of the most critical aspects of the project [8].
A list of 3D modeling tools was made (shown in Table
1) and the most appropriate was selected by the process
of elimination. Learnability and efficiency were given
more importance as a part of the REAL methodology.
Maya, 3D Studio Max, Lightwave, and Blender were
some of the software considered.
Table 1. Comparison of 3D Modeling Software
Number
1
2
3
4
Software
Maya
3D Studio Max
Lightwave 3D
Blender
Manufacturer
Alias Inc.
Discreet Inc.
NewTek Inc.
Open Source
3.3. Selection of the Engine/Driver
The engine or the driver is important from the
animation point of view. Models designed using the
selected software can be brought to life by using the
driver. Efficiency and learnability were of prime
concern while selecting the driver. The drivers
evaluated (shown in Table 2) were Object-oriented
Graphics Rendering Engine (OGRE), Crystal Space,
Genesis 3D, and 3D Game Maker.
Figure 1. Theoretical model for the VR tool
Table 2. Comparison of Engine/Driver
3. Methodology
Number
1
2
3
4
This section describes the different methods
employed to approach the problem and obtain the most
appropriate set of tools required to setup a VR-based
system for teaching pedestrian safety. These steps are
based on the REAL methodology [6] where relevance,
efficiency, attitude, and learnability are considered.
Driver
OGRE
Crystal Space
Genesis 3D
3D Game Maker
Manufacturer
Open Source
Open Source
Open Source
Game Makers Inc.
3.4. Selection of Hardware
3.1. Selection of Location
The hardware is one of the most critical component
of a VR-based system.. It is very important that the
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hardware is able to provide the necessary processing
power in order to obtain a smooth and flawless audio,
visual, and animation output. Table 3 shows the typical
hardware specifications for the proposed VR tool.
4.2. Design of the Test Models
The basic features and tools of Maya were used to
model the houses and trees for the background.
Different parts of the models were constructed and
merged together with textures. It is considered a good
practice to split any given model into different
components and construct them independently [9].
Once these components are created, they can be
imported into a single file and put together. The
rendered model of the house is shown in Figure 3.
Table 3. List of hardware and specifications
Number
Hardware
1
Computer
2
Graphics
Adapter
3
Audio
4
Display
Sensor
device
5
Component
CPU, RAM
CPU, RAM
Audio card,
Speakers
Monitors
Sensor
mat/pad
Specification
Speed,
Capacity
Speed,
capacity
Audio
qualities
Size
Sensitivity
4. Design
The design of the prototype is described in terms of
developing the models for the virtual world and the
animation of the designed models.
4.1 Design of the Proposed Configuration
Figure 3. Rendered 3D model of a house
The main idea of this project is to design a useful
and cost-effective VR technique to teach children to
safely cross roads. This section illustrates the proposed
design for such a tool. Figure 2 shows a schematic of
the proposed design, which is based on a partial CAVE
like arrangement. In Figure 2, A represents the setup of
five screens that will simulate a field of view of 180°
and will present the virtual environment to the user D.
This arrangement of the screens is similar to a CAVE
mentioned earlier. However, the setup shown in Fig. 8
can be more realistically considered as a partial CAVE
since it does not cover the complete field of view of the
user D. B is the pressure sensor mat that represents the
curb. The audio effect will be provided by the surround
sound speakers C.
The rendered model of the tree is shown in Figure
4. The complexity in terms of the number of polygons
was high, which meant that they required a longer
rendering time. These houses and trees were replicated
with minor modifications and used as additional
models for the virtual environment.
Figure 4. Rendered 3D model of a tree
Figure 2. Proposed design for the VR tool
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detail. Figure 8 shows a sample virtual environment
used for the study.
A model and texture for the car was created using
Maya. Figure 5 and Figure 6 show the un-rendered and
rendered model of a car.
Figure 5. Model of an automobile without textures
Figure 7. 3D Model of an Avatar
5. Implementation
The virtual environment shown in Figure 8 is
obtained as a result of the design process described in
previous section. The house and tree represent the
background in the virtual world. A few more models of
houses and trees may be added in order to make the
scene more realistic and complete. Once this is
achieved, the next important objective is to introduce
the interactive animation.
Figure 6. Rendered model of an automobile
4.3. Design of the Avatar
Maya, like many other 3D modeling packages,
provides a kinematics design of the human form. This
allows different body parts to move in conjunction
with one another. The main advantage of this feature is
the realistic appearance of the avatar. Figure 7 shows
the avatar of a girl with hands stretched out.
This model is not textured in order to show the
complexity of the polygons that go into it. The most
interesting part in the design of the avatar was the
introduction of the bones that follow the kinematics of
human motion.
4.4. Design of the Virtual Environment
Figure 8. Rendered model of a virtual environment
All of these individual components can be put
together to show the virtual environment in greater
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to eliminate any wires from the user’s view and allow
the user more flexibility to the user in terms of
positioning.
5.1. Configuration of the Hardware
A computer with 3.2 GHz processor, 2 GB of RAM,
NVIDIA GeForce 6600 GT graphic adapter, and 40GB
hard disc drive (HDD) was selected. The pressuresensor mat is also defined in the proposal along with
the surround-sound audio system. However, during the
course of the project, certain modifications were
introduced in the design and setup of the equipment.
The original proposal of including five screens to give
a 180° field of view was altered in order to reduce the
complexity of the design for the prototype. Instead of
the proposed setup, a decision was made to use a single
large screen for the display. This would give a desktop
type of VR, suitable for a prototype. Moreover, the
author has also suggested on using a mouse instead of
the pressure-sensor for triggering the animation.
Normal speakers could be used for the audio effects
without compromising the quality of the prototype.
5.3. Animation Driver
The 3D animation driver was implemented using the
3D game maker. The 3D game maker provides precompiled drivers that can be incorporated into an
existing 3D environment(s). The animation and
collision-detection driver was successfully utilized for
the experimental setup [10].
6. Discussion
Different 3D modeling tools were analyzed during
the course of the project. Their features, rendering
abilities, animation, and interface features were studied
and compared. Special attention was paid to cost, and
to the popularity of the tools in the professional
graphics and open source developers’ community.
Based on the author’s experiences with various
modeling software, it can be safely said that any
modeling tool can be used effectively for the models.
Most of these modeling tools lack built-in drivers or
engines for interactive animation, which puts all of
them at the same level as far as this study is concerned.
No major software was a clear winner in the modeling
software domain for this project. Maya worked
absolutely fine for the models; however, Blender is
open source and free and has similar basic features.
5.2. Structural Arrangement
Figure 9 shows a schematic for the final
implementation based on factors of cost, convenience,
complexity, and usability. A is the large set of three
flat-panel screens, B is the computer-mouse, C is the
audio system, D is the user/subject, and E is the
computer with the required configuration. This step is
simple yet effective in terms of relevance, efficiency,
learnability, and usability. The placement of the 3D
surround-sound speaker system is critical in order to
provide true audio effects for the user.
E
A suitable location was not identified for depicting
the virtual world. The reasons were obvious, in that it
would be extremely complicated to design a real-world
scene within a very short time frame. Therefore, a
fictitious scene was visualized for the prototype. The
animation engine used was the 3D Game Maker which
was very economical and easy to use.
A
C
C
The methodology used throughout the design
process was based on the REAL concept. Relevance is
important because it is very easy to digress from the
core features in such projects. The models made and
equipment chosen should have a clear relevance to the
main theme of the study. Efficiency is a significant part
of any project. One needs to select tools and methods
that are highly efficient in order to optimize cost, time,
and energy. It is good planning to define the attributes
of the constituents so as to achieve an optimal solution.
Finally, learnability is crucial for a project that is
aimed at training or teaching.
B
D
Figure 9. Modified setup for experimental test-bed
User D looks at the virtual world on screen A and,
based on the visuals and acoustics, uses mouse B as a
trigger to make the avatar start walking. This
arrangement also has a minimum number of cables or
wires that might cause obstructions or distractions for
the user. Further, the use of a wireless mouse can help
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This study was meant to provide a suitable design
for developing a VR tool for pediatric pedestrian
safety. Efforts were been made to incorporate all of the
factors that were encountered throughout the various
phases of the project. A realistic approach was taken at
tackling the problem and coming up with the design
methods and suggestions. Hence, this study is aimed at
providing a guideline for the selection of the suitable
software and hardware and the building of a virtual
environment with all the other components, and
suggestions for animation of avatars.
9. References
[1] W. R. Sherman and A. Craig, Understanding Virtual
Reality: Interface, Application, and Design. San Francisco,
CA: Morgan Kaufmann Series, 2003, pp. 12-35.
[2] Y. A. Slagen-de-Kort, et al, “Virtual environments as
research tools for environmental psychology: A study of the
comparability of real and virtual environments,” in Proc. 4th
Annu. International Conf. Presence, Philadelphia, 2001.
[3] S. Starnevall, “Traffic Simulation in Virtual Reality with
Possible Application to Rehabilitation,” Thesis Research,
2003, Lund University, Sweden.
There is a need to determine the usability and
effectiveness of the VR tool that is proposed. The idea
is more at a theoretical level and there could be
drawbacks when tested under real-world conditions.
Moreover, it is essential to know if it is acceptable to
children in the age group of five to nine years.
[4] J. Preece, Human Computer Interaction. Boston, MA:
Addison-Wesley Professional, 1994, pp. 57-89.
[5] C.E. Lathan and K.M. Stanney, Handbook of Virtual
Environments. Mahwah, NJ: Lawrence Erlbaum Associates,
Inc., 2002.
7. Conclusion
[6] S. Bryson, Approaches to the Successful Design and
Implementation of VR Applications. San Diego, CA:
Academic Press, 1995, pp. 102-119.
VR technology can be used as a training tool for
pediatric pedestrian safety. A low cost solution is
proposed, designed, and implemented in this study. An
economical solution is achieved by using off-the shelf
hardware and minimal amount of software
development. High-end hardware may be used for
better results but that will inadvertently increase the
cost. Further, the VR tool may be tested with real
subjects in a controlled environment to gather statistics
to study its effectiveness, reliability, and efficiency.
[7] L. Elliot, “Cutting Development Costs with Design
Simulation,” Desktop Engineering Magazine, vol. 9, no. 5,
January, 2003, pp. 21-25.
[8] G. A. Hotz and S. M. Cohn, “Pediatric pedestrian trauma
study: a pilot project,” Traffic Injury Prevention, National
Library of Medicine, June 2004.
[9] D. A. Bowman, E. Kruijff, J. J. LaViola, and I. Poupyrev,
3D User Interfaces: Theory and Practice. Boston, MA:
Addison-Wesley Professional, 2004, pp. 198-230.
8. Recommendation and Future Work
[10] K. Pandey, “Virtual Reality Based Tools for Pediatric
Pedestrian Safety,” Thesis Research, 2005, University of
Alabama, Birmingham, AL.
The 3D modeling tool is a very important part of a
study of this nature. Therefore it is essential that the
tool selected is the optimal one. Another feasible
option is the use of a 3D laser scanning device in order
to readily scan any real world environment. This
procedure will help in making a pure 3D background
instead of the pseudo suggested in this study [11].
[11] G. C. Burdea and P. Coifette, Virtual Reality
Technology. Somerset, NJ: John Wiley & Sons, 2003, pp. 2765.
10. Acknowledgement
This project was supported by the UAB Injury
Control Research Center at the University of Alabama
at Birmingham through a grant from the National
Center for Injury Prevention and Control, Centers for
Disease Control and Prevention, Award R49 /
CE000191 and a cooperative agreement with the
Federal Highway Administration, Project No. ICRC
(1) / PL 106-346.
The present study describes a solution with a threescreen display for the user. Such a setup represents a
desktop VR system for which immersion is fairly low.
Therefore, as a part of any future study, the original
proposal for a five-screen semi-circular display is
recommended. A pure CAVE environment with 360o
field of view would be ideal.
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