Issue link: https://digital.copcomm.com/i/18322
VR•Medical n n n n ing on the structure before some of us on this team were born,” Banfelder says. “So, he prob- ably had a good model of it in his head. But he could save the students in his lab months of time understanding the model.” Researchers also draw on the Cave to look at time-lapse photography at a molecular level using data from confocal microscopes. “Te field of view is maybe 10 cells,” Banfelder says. “We can take the slices and create 3D models of the cells. Te scientists can see the mecha- nisms of individual molecules distributed spa- tially within the cells.” Banfelder estimates that the team so far has worked with researchers in approximately a dozen labs out of the hundreds at the univer- sity, but the pace is quickening. “It took a lot of time to work with people at the beginning,” Gracia says. “We had to convince people, but now they’re starting to come to us for help.” Also, the first application of an OCT scan, the project for the ophthalmologist, took the team several months to render inside the Cave. “Now, we can do it in five minutes,” Banfelder says. “Each project goes along those lines. Ev- ery time we do one, we get better.” Next Steps As more people discover the advantages of seeing their data in the Cave, it’s likely there will be more requests than time allows. “We don’t have money or space for a second Cave,” Banfelder says. “So, one of our main criteria for the software is that it can run in stereo on the desktop so we can push the visuals out of the Cave.” Tey hope that the success of this project will inspire other medical colleges to consider this type of visualization. “Our installation was in the seven figures,” Banfelder says. “So it’s not something a single lab would ever buy. But, they could install a high-end visualization wall and get 80 percent of the benefit for 20 percent of the cost.” Even with only one visualization wall, as Borcherding points out, “someone could bring in everyone in the lab and show them what they’re working on: the model in their head.” Tis, they expect, will become increasingly important, as will Caves such as the one they have installed. Banfelder notes that today’s in- struments generate more data than people have the capability to look at. “Tere’s so much data, especially in bioinformatics, that people do one analysis and then put the data on the shelf. But the Cave can give them a way to visualize mas- sive amounts of data very quickly and detect patterns in data that weren’t anticipated.” In fact, Banfelder hopes the Cave will help inspire the manufacturers to provide more data—that is, higher-resolution images. “Five years ago, for many imaging modalities, the resolution wasn’t available for good 3D recon- structions,” he says. “Now we’re seeing that. And when we have better visualizations, they have more incentive to capture the data.” “When we told the manufacturers what resolution we wanted,” Banfelder continues, “they said, ‘What would you do with that?’ When they see the Cave, they know. We want to inspire them to improve the resolu- tion, to go as high as they can, to get finer slices, less distance between the cut plates.” In addition to encouraging other labs to create high-end visualization systems, the team has entered into conversations with manufacturers and drug companies that might provide the same types of visual representations. “We’re starting to talk to instrument manufactur- ers,” Banfelder says. “In the OCT world, for example, everyone looks at slices, and there has been no access to true 3D reconstruc- tions for the average physician who has one of these scanners. We are talking to manufactur- ers about rendering these reconstructions on a computer attached to a scanner so it could become a standard of care.” Someday, thanks to the inspiring work from this team, we might see that ophthalmology sur- geon wearing the head tracker in his own office, rather than jogging up two flights of stairs. n Barbara Robertson is an award-winning writer and a contributing editor for Computer Graphics World. She can be reached at BarbaraRR@comcast.net. Building a Cave Doug Boyer, sales manager with Christie’s Visual Environments team, had been working with Cornell University in New York when he heard that the Cornell’s medi- cal college was interested in a VR Cave. “I was the last vendor on board,” he says. Before long, he was directly involved in installing that Cave. The biggest challenge for the installation was the small room. “Originally, we proposed a 96x96-inch viewable screen for the three walls and floor,” Boyer says. “After doing the site survey and carrying a physical mock-up through the building, we determined that the largest screens could be 93x93 inches. For the screens, Christie had acrylic surfaces manufactured with a special diffusion coating. Although some vendors suggested installing four to eight LED projectors on the front wall and four on the sides, the solution Christie devised used two, three-chip DLP projectors with Xenon lamps for each of the three walls and the floor—a total of eight Mirage HD3 projectors. “At the time of the [Cornell] installation, we were the first to market with native HD DLP projectors,” Boyer says. “Each projector had 1920x1080 resolution; we edge-blend to create an overall 1920x1920 resolution; the projectors have edge- blending and image-warping capability built in.” The projectors display the images in active stereo. “They take in 60 Hz, line dou- ble, and display 120 Hz,” Boyer says. “The user wears shutter glasses that flicker at 60 frames per second per eye.” Helping make edge blending possible was Christie’s wide range of lens sizes for the projector. “You have to find a balance when you’re doing edge blending,” Boyer says. “You don’t want a short throw. We had to take into account the throw distance and the quality the image would have. To shorten the throw distance, we used mirrors that bounce the projected light off the screen; we actually bend the light using these glass mirrors.” Inside the Cave, a motion-tracking system captures the user’s eye movement via a wireless device mounted on the 3D glasses, and receives input from an interaction device—a handheld wand with multiple buttons. “It tracks the head and the wand simultaneously,” Boyer says. People inside the virtual environment see the perspec- tive view from the person with the head tracker and wand. In addition, the system includes surround sound. Once Christie received all the parts in the company’s Ontario office, the installation team built the entire environment there before taking it on the road. “We built it in Kitch- ener [Ontario], then tore it down, shipped it to New York, and assembled it there,” Boyer says. “Now, we go back twice a year to replace lamps and filters, dust off the mirrors, do color balancing, and tweak the tracking as needed. –Barbara Robertson October 2010 31