Issue: Volume: 24 Issue: 4 (April 2001)

Bright Lights, Big Picture

The future of the big screen never looked so bright. Visualization researchers at the San Diego Supercomputer Center, in collaboration with the JVC Digital Image Technology Center, have developed a tiled display technology that promises to raise the power wall concept to new heights. Called the High-Density Display (HDD), the innovative system utilizes a novel tiling approach and custom optics to provide high-quality, high-density views of large, complex datasets.

Most of the tiled display systems available today rely on matrices of video projectors that are configured to produce a single large output image. The resulting display, while of sufficient resolution to accommodate large datasets, often lacks uniformity across the multiple tiles because of optical variations among the projector units. "The output of any one tile typically does not match the color and intensity of its neighboring tiles," according to John Moreland, the lead engineer on the HDD project. In addition, because most tiled displays occupy a significant amount of space, viewers who want or need to see the entire display must observe it from far away or move close and walk from side to side to pan over the image tiles.

In contrast, viewers using the HDD observe uniform imagery over every tile of the display, and they are able to see the entire HDD projection without having to change their physical viewing location and without losing any detail. The factors enabling this are the display's reliance on a shared light source and a fiber optics-based light distribution system, for which the SDSC and JVC currently hold a one-year provisional patent.
The high-density tiled display system under development at the San Diego Supercomputer Center is driven by multiple projectors and a tightly packed optics configuration that provides image uniformity across all of the tiles, each of which produces a 21-in

The HDD light source provides uniform intensity of light for all tiles, and because it is a single light, the uniformity is maintained even as the lamp ages. Similarly, shared color filters provide the same red, green, and blue color hue to each tile's optics module. The light and color is distributed evenly among the modules by a randomized fiber optic delivery system.

The HDD tiles themselves are capable of higher density, higher resolution projection thanks to a custom, tightly packed optics configuration. The special set-up enables each tile to produce a 21-inch diagonal display and a native 1280-by-1024 pixel image.
A randomized fiber optic delivery system (above) carries and distributes light and color evenly among the HDD projection modules. In addition, because the HDD doesn't require as much space as most tiled displays to achieve high resolution, viewers can

The SDSC Visualization Lab currently houses and is further developing an HDD system configured in a 3-by-1 tile arrangement. The researchers plan to expand this to 3 by 3 tiles, which will enable an unsurpassed resolution of 3840 by 3072 pixels-11.8 million pixels. With this enhanced display, says Moreland, "scientists will be able to view their complex digital data sets at near film resolution."

Because the HDD is able to maintain color and brightness uniformity across the tiles, "scientifically meaningful" color maps make observations of digital data more visually and technically accurate than that which can be achieved using current tiled display technologies.

Among the many potential beneficiaries of the new technology are scientific and medical researchers who are often hampered by the inability to fully appreciate the increasingly large, complex datasets they have at their disposal thanks to explosive advances in simulation and computational technology in recent years.
The jumble of wires and fiber optic equipment behind the HDD projection area are key to the display system's ability to project complex, high-resolution imagery without loss of detail.

One of the applications the HDD team members have used to demonstrate the capabilities of the display is a medical imaging project at the University of California/San Diego (UCSD) Cancer Center. Medical researchers there generate visualizations of brain cancer cells by photographing serial slices of frozen brain tissue. Each of the individual tissue slices has a resolution on the order of 2000 by 2000 pixels. With such high-resolution datasets, says Moreland, "a standard 1280 by 1024 monitor is already insufficient to show the entire sample." With the new display technology, he notes, "scientists are able to see the very fine detail of important areas, such as a tumor in the brain, while at the same time seeing the overall context of the entire head."

When the provisional patent on the new technology expires (the duration of such patents is one year), the researchers anticipate a full patent will follow given the uniqueness of the underlying components. In the meantime, the team is in the process of submitting a funding proposal to the Department of Energy to develop prototypes of the display system, with an eye on the commercial market, according to Bill Bleha, vice president of engineering at JVC's Digital Image Technology Division.
A visualization of the Orion Nebula was displayed on the HDD at a pixel resolution of 3840 by 1024, providing scientific researchers with an unmatched view of the stellar phenomenon. (copyright 1999 VisLab SDSC)

Ultimately, says Bleha, "we hope to market the HDD either as one of the highest resolution displays in the world, or to develop and market the [optics] modules, which customers can configure into their own displays." More information on the HDD can be found at display.

Diana Phillips Mahoney is chief technology editor of Computer Graphics World.