Let's go back today to -- one of -- my roots: 3-D visualization. With the help of new 3-D video displays, scientists and others will be able to interact with their experiments in novel ways.
David H. Freedman is our pilot.
Three-dimensional holographic video images will be generated by a computer rather than being fixed in a static medium; they will be shown in full-motion color and, with input from a user, changed on the fly. What’s more, viewers who move around a holographic video image will be able to see it moving from every side -- a phenomenon important to realism and one that many conventional eyeglass-based systems cannot replicate.
The mainstream of doctors, scientists, researchers, and new-product developers who already rely on high-end computer displays to visualize their work will see dramatic differences in this new technology. Currently their work is constrained by the flat, two-dimensional images of conventional displays. No matter how cleverly the screens are dressed up, they can’t convey all the nuances, intricacies, and immediacy of real objects in the 3-D world. Because the new video holograms produce fully 3-D images that float in space near the viewing screen, they can be examined from different angles by multiple viewers. Geophysicists examining high-resolution images of rock formations will be able to predict the location of hidden oil deposits with greater accuracy. Industrial designers will be able to modify a sports car’s body using the tip of a stylus, instantly establishing the change’s effect on overall design. Military commanders will be able to visualize the best battlefield scenario. Surgeons will be better able to determine the safest approach for removing a brain tumor without ever wielding a knife. "Someday we’re going to wonder how we used to put up with 2-D images," says Stephen Benton, who heads the Spatial Imaging Group at the MIT Media Lab.
After this introduction, the author focuses on current work being done by two groups: the New York University’s Media Research Lab, which is working on cheaper solutions; and the MIT Media Lab.
The MIT effort has from the beginning focused on true holographic video, which not only holds out the promise of the highest-quality 3-D video images, but also provides the most daunting technical challenges.
The article describes in detail these challenges and the MIT’s Mark II Holographic Video. Here is an illustration of the Mark II.
A story like this one would not be complete without -- big -- numbers.
The system has some way to go, though, before it’s likely to be commercialized. The biggest problem is that making a video hologram requires crunching enormous amounts of data. That may not be surprising, given that a hologram provides not just a single view of an image, but all views from any number of angles. Still the diffraction pattern from just one high-resolution hologram can easily use up more than a terabyte of data -- enough to fill 1,600 compact discs. A moderately flicker-free holographic video would require at least 20 such holograms per second. Clearly, churning through 20 terabytes worth of information every second would require extraterrestrial technology: today’s fastest PCs operate at one- hundred-thousandth that rate. As a result, the Mark II accepts a number of compromises in image quality in order to bring the computing requirements down to a manageable 16 megabytes per second.
Source: David H. Freedman, MIT Technology Review, November 2002 Issue
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