Toshiba demos ‘Lytro chip,’ converts phones to light-field cameras
By Jay Alabaster
Toshiba plans to add something new to the tiny cameras in smartphones—depth.
The company is developing tiny image modules that can shoot “light-field” photography, similar to the cameras sold by U.S. startup Lytro. Production is to begin at the end of this year or shortly after, meaning that smartphones with Lytro-like cameras could hit the market next year.
Toshiba says its modules and accompanying software will let give smartphones the ability to refocus, accurately pluck out specific people or objects from crowded shots, or capture gestures such as taps in midair. Light-field images contain data that can be used to calculate the distance of objects captured, or focus photos or videos on user-selected points after they’ve been recorded.
Toshiba showed a test unit to IDG News Service at its research laboratory in Kawasaki, just outside of Tokyo. The cubic module measures about 8mm on each side, small enough to fit in a modern smartphone, and currently uses a traditional 8 megapixel image sensor to produce images with a resolution of 2 megapixels.
“We use much of the data not for resolution, but for determining distance,” said Hideyuki Funaki, a researcher at Toshiba.
The additional processing also takes slightly longer, but he said the current version of the module can shoot video at a respectable 30 frames per second. A future version of the module will use a 13 megapixel sensor to produce light-field images with 5 or 6 megapixel resolution.
The modules use a standard CMOS image sensor and main lens, with a sheet of tens of thousands of tiny “microlenses” between the two. Each of the tiny lenses corresponds to about 20 pixels, which capture the same scene at slightly different angles, data that can then be analyzed to produce distance information or refocus.
The distance of every object captured using the camera module can be estimated accurately out to about a meter away, with precision that varies from millimeters to centimeters. This means tasks that are difficult for current cameras, like distinguishing between large objects that are far away and small objects that are near, becomes trivial, at the cost of some resolution.
“Most cameras try to distinguish objects by color, not by distance,” said Funaki. “Phone camera modules already have more resolution than most users require.”
In December of last year, Toshiba said it would soon begin shipping samples of 20 megapixel CMOS chips.
In demonstrations recorded by Toshiba, the new modules allowed users to easily pick individuals from a group shot on which to focus, a feature that could come in handy for pictures taken in crowded places. Another demonstration showed it separate a doll photographed in one background and place it in another.
As it moves toward production of the new modules, Toshiba is working to improve its algorithms, to attain better speed and distance accuracy as well as lessen the load on a phone’s central processor.
Toshiba, the world’s second-largest NAND flash maker behind Samsung, is aggressively expanding into mobile image sensors. The company is aiming for a 30 percent market share in CMOS sensors for digital cameras in the fiscal year that ends in March 2016.