A More Realistic View
Written by Peter Buxbaum
MT2 2010 Volume: 15 Issue: 3 (May)
NEW PROJECTORS AND AUTOMATED SOLUTIONS ARE PROVIDING HIGHER-FIDELITY VISUAL SYSTEMS.
The U.S. military is increasingly demanding immersive training and simulation environments to prepare warfighters for a variety of missions and tasks. These large scale training systems invariably require the use of multiple projectors to display a coordinated set of images across a set of large screens.
This approach to training systems has created a more complex technology environment and has challenged developers to deliver projectors with ever increasing levels of fidelity and resolution, as well as projection units that work as a system to provide the kind of training environments that the military demands.
NEW PROJECTORS
Innovations in projection systems also include satisfying demand for specific mission applications, most notably for night vision. They also endeavor to enhance the efficiency of training systems by reducing the costs of operating the systems and by automating the task of calibrating the images emanating from multiple projectors.
“What we are seeing on the projector front is an increase in resolution, which allows us to configure a display system that is approaching or meets eye limiting resolution,” said Mike Raines, vice president for simulation at 3D Perception, a company that provides complete display systems. “That is no small task, especially when there is large field of view.”
A Norwegian company, projectiondesign, recently introduced two new projectors capable of supporting higher image resolutions and which provide several other features advantageous to the system approach required of today’s training and simulation systems. “Many systems need a lot of pixels to project realistic images on curved surfaces or on domes so that the user is enveloped by the picture,” said Anders Løkke, projectiondesign’s international marketing and communications manager. “We create projectors that don’t take up a lot of real estate, are easy to maintain and have high image performance.”
The F35 series projector, which projectiondesign introduced last year, is the world’s first, featuring the Texas Instruments WQXGA DLP chip, and offers 2,560 by 1,600 pixel resolution. “The resolution provided by the F35 is almost double any other projector,” said Løkke. “These projectors are included in systems where you have to make sure the image is absolutely flawless. The picture the user sees is better than 20/20 vision. There is no limiting factor in this system other than the human eye.”
The WQXGA chip features 78 percent more pixels than the WUXGA, which has 1,920 by 1,200 resolution, and offers more than five times the resolution of a standard eXtended Graphics Array (XGA) display. This also results in increased system efficiency, according to Løkke.
The result is a high pixel-density display that requires fewer projectors to produce ultra-realistic images. “For the same number of channels you now get more pixels, and that is of great benefit in visualization and simulation, where the emphasis is on fine detail and the accurate rendering of images,” he explained. Increasingly demanding night operations and advances in sensor system technology utilized in aircraft and other operational vehicles have led Christie Digital, a maker of projection systems, to push the envelope of display systems beyond the visible with its development and introduction the Christie Matrix StIM, a scalable environment projection system. Matrix StIM has been selected for use in deployable helicopter simulators. “It’s more than a visual projection system since it provides not only imagery in the visible spectrum, but also that in the near-infrared spectrum designed specifically to stimulate operational night vision goggles,” said Dave Kanahele, Christie Digital director of simulation solutions.
The Matrix StIM uses an independent infrared LED (lightemitting diode) in addition to the conventional red, green and blue LEDs, to create what Christie calls InfraRGB. “We are currently expanding the system level capabilities of Matrix StIM to take full advantage of this technology,” said Kanahele. “We are working closely with our customers to develop the optimal drive strategies to leverage our unique InfraRGB system to create a truly physicsbased IR scene which enables new levels of night vision goggles training capabilities.”
The incorporation of LED light sources into projectors is a development that has captured the imagination of some systems providers. “The cost of ownership for LED projectors is very low,” noted Raines. “The initial cost for LED projectors today is still a bit higher than normal, but after 12,000 hours of operation you’re already at break-even compared to lamp-based projectors because you don’t have to replace the light source.”
LEDs boast very long life times of sixty- to eighty-thousand hours, as compared to one- to two-thousand hours for lamps. “LED technology has not yet been perfected,” said Raines. “They emit 500 to 600 lumens as opposed to several thousands of lumens for lamps. But the benefits of the color and the long life of the light source are very beneficial to users, and it’s only going to get better.”
Products offered by projectiondesign tackle issues stemming from projector light sources from a different angle. The company’s FR12 series, also recently introduced to the market, also focuses on system efficiency from the standpoint of costs and improved uptime. The FR12 relocates the lamps from the projector to a rack-mount enclosure up to 30 meters [98 feet] away from the projector head. The FR12 also increases image performance by running light through a liquid light guide. “This makes the picture more uniform and easier for the system integrator to set up,” said Løkke. “We believe this will become standard over the next few years.” One of the major challenges presented by multiple projector display systems is to calibrate the projector’s images to create a seamless visual effect on the screen, and to adjust color intensity to create uniformity. Historically, this task has been done manually by a technician, a process which can take days of work. That fact, combined with the tedium involved with the task, often left manually calibrated display systems with less than optimal setups.
AUTOMATED SOLUTIONS
Several companies now automate this difficult task. Scalable Display Technologies provides a camera feedback mechanism called Easy Blend that takes a picture of the display with a digital camera and automatically calculates the adjustments to the projectors. “With the information collected in the pictures, the system calculates how to fade light and make a perfect intensity match,” said company CEO Andrew Jamison. “It is also able to move pixels around so you have a perfect match at the sub-pixel level in the blend zone.”
This type of system improves on the previous generation of automation, which allowed technicians to drop grid patterns on top of one another to coordinate the screen zones covered by different projectors. “For years this produced reasonably acceptable results,” said Jamison. “But one problem is that units move as they heat up and cool down. This requires another calibration. Customers prefer to have the ability to push a button and move through the process at one minute per projector.”
Easy Blend also includes an optional feature that allows users to automatically adjust color intensity. “As projectors age you begin to get a drift in color,” said Jamison. “No longer does blue sky get projected with a consistent shade.” The Easy Blend feature is able to adjust projectors and create a color intensity match.
Easy Blend has been incorporated into systems provided to the U.S. Marine Corps, Navy, Air Force and Coast Guard. A recent application had Easy Blend incorporated into a bridge simulator system that General Dynamics developed for the Navy for its Littoral Combat Ship. Other recent deployments of Easy Blend went toward a retrofit of the Marine Corps’s Marine Common Air Crew Trainer – Prototype (MCAT-P) and for a Coast Guard helicopter trainer.
Mersive Technologies also provides a camera-based solution to the projector calibration dilemma. “By understanding where the images are in three-dimensional space and how they interact with the surface of the display, we calibrate a line of multi-projector displays and make it much easier to get a lot more pixels out of the display,” said Christopher Jaynes, the company’s chief technology officer. “The mathematics embedded in our software allows the system to take a pattern and reroute pixels to the right point on the display. It also adjusts color intensities, reconciles areas of projector overlap, and straightens out lines.”
Mersive’s main product is called Sol server, which is a system for automatically aligning multiple projectors. “The camera instructs the projectors to generate patterns,” Jaynes explained, “and then it processes those patterns to derive a set of warp and blend equations to create a seamless image.”
Mersive also provides a camera-based color solution as part of Sol. “We don’t need to know anything about the projector,” said Jaynes. “We measure the color through the camera and then develop a description of one projector area to its neighbor. That builds out a seamless color base, and that takes only 15 seconds per projector.”
Mersive’s systems has been incorporated in training and simulation systems developed by Lockheed Martin, Rockwell Collins, and other integrators for U.S. Army and Air force flight simulators, as well as in ground-based trainers such as high-end driving simulations.
3D Perception offers an automatic alignment system that is embedded into the screen by way of light sensors that capture data on the images being projected. “The system measures the images and provides a maintenance free environment for geometry edge blending and color,” said Raines. “With more projectors and resolution in the display systems, maintaining that system to have accurate images in the display is very critical. Users are strained by all the new technology, so we need to make it easy for them, and that is what we are doing with our auto alignment system.”
Ultimately, the goal of an advanced projection system is to get multiple projectors to work as one. A new multi-image processing system was recently introduced by projectiondesign. The system, dubbed MIPS WB2560, offers high performance image blending and geometry correction for 2-D and 3-D displays and is designed to integrate with projectiondesign projectors.
“MIPS WB2560 is capable of providing image and geometry correction on a per-pixel basis for reliable image performance,” said Løkke. “MIPS WB2560 is infinitely scalable, allowing any number of channels to be combined to produce a single image. The processing engine is transparent to the image generator, and operates at or near zero latency. This makes the MIPS WB2560 perfectly suited to applications such as military event simulation, where the realism of fast-moving scenarios is crucial to the success of personnel training.”
Løkke also noted that the system’s speed ensures that images are free from compression artifacts, and that its compatibility with any resolution up to WQXGA—2,560 by 1,600 pixels—means that MIPS can blend, warp and color manage the next generation of displays.
Kanahele credits advances in image generator performance for raising the bar for what is needed on the display end of the visual system chain. “These same advances are also giving us an opportunity to provide a more integrated solution that extends the boundaries beyond what has been possible previously,” he said.
Christie Digital uses a network architecture to get multiple projectors to work as a single system. “Each projector in the array is like a node in the network,” Kanahele explained, “and each node knows about the capabilities and status of each other node. By utilizing a network infrastructure we can make them function as a system and do unique things.”
If one projector goes down, for example, it can be replaced in real time as the mission goes on. “Once the node is on the network and the network becomes aware of the new status,” Kanahele explained, “the system automatically adjusts itself.” ♦