MIT Project Ditches the Glasses, Keeps the Mobile 3-D


Improved glasses-free 3-D screens could arrive on smartphones and other handheld devices based on HR3D, a new visual system developed by researchers at the Massachusetts Institute of Technology. Unlike displays used on the Nintendo 3DS handheld, HR3D screens use less battery power and the three-dimensional effects are visible across a wider angle. That means the images can be shared with a group of people at the same time, or can be viewed without directly facing an HR3D screen.

Most 3-D displays that don’t require glasses use old parallax barrier technology: one screen shows duplicate, but offset images, while a second screen with vertical slits sits atop the first screen. By viewing the images through the slits, the eyes perceive a 3-D effect without the need for special glasses. There are two different issues with this approach, however.

Using a parallax barrier display reduces the amount of light that a screen can transmit, so the Nintendo 3DS uses approximately twice the amount of battery power as its predecessor to illuminate the display. And because the slits required for the three-dimensional effect are vertical, the screen must be viewed squarely; move off to the side and the effect is diminished. Not so with the HR3D technology developed at MIT.

Instead of relying on a set pattern for the parallax barrier, MIT researchers and graduate students designed a screen that displays a dynamic pattern:

Like the 3DS, the MIT researchers’ HR3D system uses two layers of liquid-crystal displays. But instead of displaying vertical bands, as the 3DS does, or pinholes, as a multi-perspective parallax-barrier system would, the top LCD displays a pattern customized to the image beneath it.

Going into the project, the researchers had no idea what the customized pattern would look like. But once they’d done the math, they found that the ideal pattern ends up looking a lot like the source image. Instead of consisting of a few big, vertical slits, the parallax barrier consists of thousands of tiny slits, whose orientations follow the contours of the objects in the image.

Essentially, the pattern of slits changes with the image and can even adjust for how the device is held, by using a gyroscope or accelerometer; two sensors that are fast becoming common in smartphones. The slits also allow more light to pass through the display, so there’s less of a power drain required for backlighting the screen.

Don’t expect to see HR3D screens on smartphones all that soon, however. The early designs are computationally intensive to account for the dynamic pattern changes, so all of the battery savings for now is used up by hitting the processor harder. For the moment then, I’m resigned wearing those goofy red and blue glasses while watching this 3-D video of my son skateboarding taken with the G-Slate tablet.

Image credit: Wikipedia


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