New AV systems offer sharp images, ‘green’ projection

Eco-friendly projectors can last for up to 18 school years with daily use, according to projections.
Eco-friendly projectors can last for up to 18 school years with daily use, according to projections.

New design techniques that can heighten a projector’s contrast without sacrificing brightness, and eco-friendly projectors that eliminate the need for costly mercury lamps, are among the many recent developments in audio-visual (AV) technologies with implications for schools and colleges.

Here’s a look at these and other new trends in the AV market for education.

Educators trust projectors for medical imaging

Officials at the University of North Carolina School of Medicine’s Department of Radiation Oncology make critical treatment decisions based partly on images showing where cancer cells are, so having a crystal-clear projector image is critical for accurate diagnoses.

Julian Rosenman, a professor at the university’s Department of Radiation Oncology, said black-and-white CT scans with shades of gray dispersed throughout could dictate a patient’s treatment. That’s why the department bought two of Canon’s REALiS SX80 Mark II D Multimedia LCOS projectors, which are mounted on the ceiling for stability and offer dual projection images so students and doctors can compare and contrast scans side by side.

The Canon projectors also let Rosenman and his colleagues teleconference with medical professionals and students worldwide, because the projectors’ images can be shared with doctors at other campuses or hospitals.

“We do a lot of tumor boards and telemedicine meetings, in which doctors view medical images to make treatment decisions,” Rosenman said. “This is why the color accuracy of projected images is so important.”

The Canon REALiS SX80 Mark II D projectors feature 3,000 lumens of brightness and a pixel resolution of 1,400 x 1,050. They use a projection technology that Canon developed, called Liquid Crystal on Silicon (LCOS), to achieve ultra-sharp, high-contrast, lattice-free images without the “screen door” effect that can mute the color and detail of some LCD images.

Early LCOS projectors sacrificed compactness and brightness to achieve this degree of clarity, Canon says. But the company has developed a new optical system, called aspectual illumination system (AISYS), that solves this problem. AISYS splits beams of light into vertical and horizontal components, then uses each component to enhance brightness or contrast. The result is a system that combines the kind of sharp contrast and high degree of brightness needed to distinguish between many shades of gray.

The REALiS SX80 Mark II D features a mode that complies with Digital Imaging and Communications in Medicine (DICOM) devices, because it offers 21 levels of grayscale gradation for more accurate diagnoses. Having a DICOM feature built into the device, medical school officials say, means universities won’t have to buy costly additional equipment designed to supplement the image projectors.

UNC officials said the Canon projectors also have helped the medical school avoid image disturbances caused by other electronic devices in the area—a common problem among some projectors.

“Image stability is also very important when you are comparing medical data. I don’t know how Canon does it, but the [projectors] reject the jitter … caused by the other electrical equipment we’ve got going,” Roseman said. “With these REALiS projectors, you don’t see rolling bars or visible beat frequencies.

He added: “These are the smallest, quietest, and most stable projectors we’ve ever had. They also don’t throw off a lot of heat, which is important when you’ve got 20 people in the room.”

New ‘green’ projectors do away with mercury lamps

While the University of North Carolina relies on Canon’s accurate images, other schools and colleges are using Casio’s new lineup of Green Slim Projectors, eco-friendly projectors that eliminate the need for mercury lamps that typically must be replaced after 2,000 hours of use. Mercury can cause environmental damage if not disposed of properly.

The Green Slim DLP projectors use a patented hybrid “solid state” light source, which combines laser and LED technology to achieve high brightness, instead of a mercury lamp.

Denny Carter

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