Lens-less camera, costing pennies, brings vision to the Internet of Things
Lens-less camera, costing pennies, brings vision to the
Internet of Things
By Patrick Thibodeau
Computerworld | Sep 18, 2014 12:25 PM PT
There's a type of camera technology emerging with a view
of the world similar to what a honey bee sees. The images appear blurry and
hazy, but if you're a bee, good enough for finding flowers and people to sting.
It could also be perfect for the Internet of Things by
making it cheap to add vision capability to just about anything.
This is Rambus' first proof-of-concept device.
Researchers took an off-the-shelf camera development kit, removed the cover
glass protecting the photodiodes, and replaced it with a 4 mm-x-5.5 mm glass
chip with diffraction gratings on it.
That's the idea put forth by Rambus, a company that
designs technologies and then licenses them, for its lens-less sensor. The
sensor captures light and relies on computation to shape the data into an image
that's good enough to tell whether someone is in a room or a door has been left
open. It can also be used to activate an optical lens if a higher-resolution
image is needed.
The key benefits of the lens-less technology are its
size, cost and power usage.
"What we think this technology will enable is eyes
everywhere," said Patrick Gill, senior research scientist at Rambus. He
said the technology can cut the cost of putting low-resolution imaging onto an
IoT device "by a factor of 10."
The lens-less sensor can be manufactured using processes
now used for other sensors. It is very inexpensive for product makers to add
sensors that detect motion, vibrations, temperature, pressure and noise because
these microelectromechanical systems (MEMS) are made with the same low-cost
wafer fabrication processes used for chip manufacturing. These sensors only
cost pennies.
A combination of improved manufacturing techniques and
demand is driving prices down, said Randall Restle, director of applications
engineering at Digi-Key, a major electronic components distributor.
Today, "you can get a 32-bit microprocessor for
around 50 cents apiece in reasonable quantities, like a thousand," said
Restle. "[There] has been such a collapse of price."
Camera optics are relatively expensive to make because
they take multiple parts, including a lens. The Rambus sensor uses a
diffractive phase grating technique that splits the light wavelengths, creating
a "jumble of spirals," and then computes the image from this raw
data.
The Rambus lens-less sensor is still in advanced
development, but moving into development, said Gill. The plan is to have it in
open beta or full product release in the next year or two, he said.
The lens-less approach may sacrifice high resolution, but
"the animal kingdom has shown that that kind of level of vision can be
sufficient to navigate environments," said Gill.
Gartner recently predicted that a smart building could
contain more than 500 smart devices by 2022. The estimate invites incredulity
until you consider how cheap it will be for a maker of anything to add a
sensor, wireless radio and software -- which may be open source -- to just
about anything leaving a factory floor.
This device proliferation would be impractical if
building owners had to run around replacing batteries. That's why very low
power sensing technologies will be critical, along with the development of
energy-harvesting systems that can capture energy from motion, such as
footsteps, or friction.
Gartner tracks the prices of the sensors, and they
continue to fall; the cost of enabling a device may be no more than $1 before
long.
The $1 estimate can be seen as a basic cost for adding a
network and processor chip, excluding integration costs, said Nick Jones, an
analyst at Gartner. He's also assuming that embedded software costs will be
"approximately zero" since those are amortized across a large number
of devices.
Gartner's prediction doesn't assume that all the
protocols and interoperability issues will get sorted out. Jones expects it may
take as long as two decades for that to happen.
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