Sab Babu, Department of Computer Science, College of Liberal Arts and Sciences
Sab Babu is a good guy to know during the cold Iowa winter—he can arrange a nice bicycle ride down warm, sunny streets, regardless of the weather forecast.
Babu is an assistant research scientist in the University of Iowa Department of Computer Science, and he plays a primary role in the department’s Hank Virtual Environment Laboratory. His research—funded by the National Institute of Injury Prevention and Safety, the National Institutes of Health, and the National Institute of Science, among others—uses an immersive bicycling simulator to determine factors that play a part in bicycle-vehicle accidents involving children.
He also has helped develop virtual environments that allow theatre players to practice their lines and let eyewitnesses conduct a lineup viewing without potential bias.
Babu sat down with fyi to talk about what his team has learned through the bicycling simulation sessions, what he loves most about his work, and how he continues to shine on the badminton court.
Tell us a little bit about the bicycling simulator and your research.
This simulator is one of the few high-fidelity virtual reality bicycling simulators in the world. Three screens measuring 8 feet by 10 feet are placed at right angles relative to one another and a stationary bicycle is mounted in the middle of this arrangements. Three projectors are used to rear-project the virtual imagery onto the screens, providing participants with 270 degrees of immersive visual imagery. The viewpoint of the scene is adjusted for each rider’s height, to provide an accurate perspective.
We use the bicycling simulator to study the perceptual-motor factors that put children at risk of accidents when crossing busy intersections on a bicycle. Bicycle accidents are a common cause of injury in school-aged children; approximately 600,000 bicycle-related injuries are treated in emergency rooms each year. Our studies compare the relative performance of kids and adults in the bicycle simulator, using carefully simulated traffic scenarios.
What have you learned through the simulations?
The simulator exercise involves a bicyclist proceeding through intersections with nonstop vehicle cross traffic. One of the key findings suggests that children and adults proceed through the intersection during the same sized gaps in traffic, but children leave less time to spare with regard to the trailing car. There are several reasons for this: children delay their start when crossing the intersection, and they also ride at slower speeds compared to adults.
Have you fine-tuned the simulator for certain aspects of the study?
In the past year, I introduced a virtual peer bicyclist in the immersive virtual reality bicycling simulator so we can study social influences in children’s bicycling. The virtual bicyclist’s repertoire of behaviors includes road following, riding alongside the human rider, stopping at intersections, and crossing intersections through specified gaps. The virtual cyclist engages the human subject through gaze, gesture, and verbal interactions.
We learned from a pilot study with the virtual peer system that the presence of the peer had a significant influence on the size of the traffic gaps taken as well as time left to spare between the participant and the trailing car in the crossed gap. Kids took riskier small gaps in traffic when they rode with the peer than when they rode by themselves.
Are faculty and staff welcome to participate in these simulation projects?
Absolutely. We often distribute fliers and announcements to let people know about these experiments. We are constantly running experiments with both kids and adults in our bicycle simulator to study how the behaviors of kids and adults differ based on their perception of their environment. Some experiments look at differences in distance perception or speed perception in the virtual world. These all have implications as to how kids and adults react to environmental visual stimuli.
What other simulation projects have you worked on?
My PhD dissertation involved studying how people respond to interactive virtual humans in interactive 3D applications such as virtual receptionists and immersive training applications. I created immersive virtual environments to teach and train users interactively how to learn social conversational conventions in a foreign culture.
One of these projects includes a project called Shakespearean Karaoke, in which we created an interactive virtual environment in which participants can practice their lines of a Shakespearean play by interacting in a natural manner with a virtual actor.
Another project is called Officer Garcia, which involves the use of a virtual human to mediate a suspect lineup. This project was conducted in collaboration with the departments of computer science and psychology at the University of North Carolina–Charlotte and the Charlotte Mecklenburg Police Department. The goal of this project is to provide a consistent approach and natural approach to the suspect lineup process that eyewitnesses find easy to use. It is a step in the prevention of false convictions due to personal bias that can be introduced by a human mediator in the suspect lineup process. (Watch the video below to see Officer Garcia in action.—ed.)
What is the most rewarding thing about your work?
Every spring, I have been teaching the special topics course on virtual environments and embodied conversational agents here in the Department of Computer Science. This course introduces senior undergrads and graduate level students to the software, hardware, and algorithms of virtual environments and virtual human technologies. I immensely enjoy teaching and working with students, and take pride in my teaching. It is a very gratifying experience to see how great students feel when they create such wonderful virtual environments. Along the way, they learn important problem-solving skills that will help them in all walks of life.
What is your favorite thing about working at The University of Iowa?
I love the location of the University, and our department in the center of Iowa City. The University of Iowa is very scenic. When I visited the University for the first time, I was taken by the architecture, the downtown location, and the multicultural atmosphere of the University. It’s a pleasure to work in MacLean Hall, and I also enjoy the many ethnic restaurants and coffee shops in downtown Iowa City.
What do you like to do in your free time?
In my late teens and early twenties, I was a national-level badminton player. I also played at the collegiate level, representing the University of North Carolina–Charlotte in collegiate badminton tournaments across the country. Although retired, I am now a member of the University of Iowa Badminton Club—I play at least three times a week with the club at the Field House.
I’m now a certified coach; my dream is to open a badminton training center for youth. I am currently teaching badminton on the weekends to the children of some faculty and staff who play in the Badminton Club. Maybe one of them might end up playing in the Olympics some day!
Any chance you could simulate warm weather for us each winter?
Ha! It is a good question, given the cold spells we have had in recent weeks. The weather in our virtual environments is always sunny and tropical—you are welcome to escape the cold weather and enjoy biking in our simulator.
by Christopher Clair