By Dave Ghose. Photos by Jo McCulty

Transcription

1

2 odies in M Members of Bebe Miller s dance troupe include, clockwise from above, Sarah Gamblin, Angie Hauser Robinson, Kathleen Hermesdorf, Darrell Jones, and Ted Johnson 2 OHIO STATE December 2002 By Dave Ghose Photos by Jo McCulty

3 o t i n o Along with its gee-whiz applications, motion capture technology is just plain fun B EBE MILLER HAS PERFORMED ON STAGES THROUGHOUT THE WORLD, BUT NEVER IN A VENUE LIKE THIS. Miller s troupe of five dancers is sprawled on the carpet at Ohio State s Motion Capture Lab. Small reflective balls more than 40 per dancer stick to their tights, leotards, limbs, even toes. In a few minutes, they will perform while 14 cameras capture every leap, spin, and kick. Miller, a professor of dance at Ohio State, has spent the past week watching her dancers perform in the bizarre outfits. In the lab s nearby control room, she also has watched little stick figures on a computer screen: three-dimensional recreations of the dancers motions. The stick figures, which mimic the dancers precisely, have started her creative juices flowing. Soon Miller will test the technology herself. She ll strap the balls to her body and let the cameras record her movements. I m so psyched, she says. I can t wait to do it. Since April 2001, Miller and several other Ohio State researchers have been experimenting with the Motion Capture Lab. Such a facility is a rarity on a college campus. Most people associate motion capture technology with big-budget Hollywood movies or sports video games, but its supporters at Ohio State believe it has much broader appeal. It can be used for anything you can think of, said Suba Varadarajan, a graphics research specialist who supervises the lab. Indeed, a number of faculty members are using the 3,500-square-foot lab, which is part of the Advanced Computing Center for the Arts and Design, or ACCAD. It has attracted users from departments including theater, computer science, psychology, and veterinary medicine. The numbers will grow as word continues to spread, researchers predict. The Motion Capture Lab is located at Ohio State s Science and Technology Campus on Kinnear Road. Vicon Motion Systems of England made the equipment, which includes eight wall-mounted cameras and six cameras on tripods. The cameras surround a black- OHIO STATE December

4 painted room with high, exposed ceilings. Cables link the cameras to computers in a control room behind a glass window. For the cameras to work, the subject must wear a skin-tight outfit with reflective balls, or markers, attached to it. The balls are placed around joints to give an accurate reading of the model s movements. Each camera is equipped with a red light that illuminates the balls and allows their locations to be recorded. From there, the information goes to the computer. An outline of dots appears on the screen. Technicians then link the dots, creating the stick-like 3-D figures. The Vicon system is considered top of the line, with each camera taking 120 shots per second. Ohio State is one of about 10 universities in the country with such a lab. The College of the Arts, the Office of Academic Affairs, and the Office of Research paid for the $250,000 equipment, and another $150,000 went to renovate the space. The college and the university saw it as another opportunity to push the frontier on what is being done in graphics research, said ACCAD director Maria Palazzi. And they also saw it as a lab that would help to foster more multidisciplinary relationships, and that is exactly what has happened. One week, there is a psychologist in there. The next week, there s a computer scientist in there. The next week, there is a dancer. Since it started in the 1970s, ACCAD has tried to foster an atmosphere where scientific investigation meets aesthetic ideals, and everyone is encouraged to use technology in innovative ways, according to its Web site. Palazzi says the Motion Capture Lab is a prime example. There is just this incredible experience the students end up having, because they are all mixed together in there, she said. And they are using this technology in ways that even we would never dream of. It is just this incredible mix of all these different disciplines finding things in common as we cross over from one field to the other. The Motion Capture Lab debuted with a bang, albeit a silent one. In 2001, during his third Ohio State residency, world-famous French mime Marcel Marceau gave a performance in the lab, then housed in a temporary location in Mount Hall on west campus. The cameras and computers captured Marceau s subtle movements, even his breathing. The virtual record now is part of the university s Mime and Movement Arts Collection, helping to preserve the performer s work and assuring that his skills and artistic knowledge will live on after he dies. To make sure the debut went smoothly, an Ohio State alumnus with ties to a leading Hollywood visual effects company handled the proceedings. Jeff Light, motion capture supervisor at Industrial Light and Magic (ILM), has worked on such films as The Phantom Menace, The Mummy, The Perfect Storm, and Jurassic Park. ILM and Hollywood studios have put motion capture to good use in recent years. So has Electronic Arts, which has used the technology to create videogame versions of just about every major sport. As a result, plenty of people associate motion capture with entertainment. But Palazzi lists about a dozen other possible applications. Biomechanics, sports medicine, and interior design are just a few. Caroline Palmer, a psychology professor, used the lab to analyze the finger movements of a pianist. She s looking at how a person is reading music and making decisions about what positions your hands should be in, Palazzi said. Theater professors used the lab to create a virtual classroom. Using a computer interface, students can make decisions about lighting, movement, costume, and sound. Before, only those in small, focused classes could practice such skills. Veterinary medicine students also may benefit. The lab recorded the motions of dogs 4 OHIO STATE December 2002

5 Left to right: Suba Varadarajan, Bebe Miller, and dance company members Angie Hauser Robinson and Ted Johnson study how the dancers motions translate to the computer screen. OHIO STATE December

6 with hip problems and other ailments. Teachers can show the motions to vet students who can try to diagnose what s wrong with the animals. Because it s hard for vet students to see all those kinds of things in their schooling, this is a way to visualize them, Palazzi said. James Davis, an assistant professor of computer information science, has used the Motion Capture Lab regularly since it opened. He came to Ohio State in 2000 after earning his doctorate from MIT. For more than a decade, he s been searching for ways to help computers understand and recognize human motions. The lab is a big attraction for him. It opened right after I got here, which actually was wonderful timing, he said. Davis has set up an office in the same building as the lab so he and his collaborators can have easy access to it. We are interested in human motion and human activity analysis, he said, and that is where the Motion Capture Lab comes into play. We are interested in capturing the full three-dimensional movements of people, from walking, running, skipping, throwing. Before the lab opened, Davis briefly used video cameras for his research. He was trying to see if a machine could tell the difference between a child walking and an adult walking, based on movement. We went out and got little reflective-tape-and-velcro patches and strapped them on people and took a video camera, and then did all the processing ourselves, he said. It was a nightmare to do. Davis estimates he would need a thousand video cameras for full 3-D viewing, which the Motion Capture Lab produces easily. So once this lab was up, we ditched all that stuff and went straight to this system, he said. Bebe Miller booked the lab for two weeks in early October. Miller, an Ohio State graduate, has choreographed works for the Boston Ballet, Oregon Ballet Theatre, and PACT Dance Company of Johannesburg, South Africa. She joined Ohio State s dance department in 2000 and became interested in the new Motion Capture Lab shortly after that. Miller has begun developing a new piece and expects to work on it for the next three years. At this point, she sees the lab as a way to evaluate what she s doing and discover new avenues to explore. You look at a figure on a screen, and say it s one of the dancers dancing, she says. Every inflection of his movement and personality is there. I can then play with that. I can enlarge it. I can try to set it on someone else s body. I can make something with that. Then maybe we can learn from it and put it back into the body. Miller now is thinking about using the technology to create an animated dancer for her work. It s so fun, she says with a laugh. David Ghose is a frequent contributor to OSAM. For more information about the Motion Capture Lab, visit 6 OHIO STATE December 2002 Bebe Miller

7 OHIO STATE December