Engineers have created a new way to stream HD video from a wireless camera with far less power than current technology.
Wearable cameras offer incredible promise, but because these cameras must use smaller batteries to stay lightweight and functional, these devices can’t perform high-definition video streaming.
The new prototype, however, skips the power-hungry parts and has something else, like a smartphone, process the video instead.
Backscatter breakthrough
The researchers achieve this with a technique called backscatter, through which a device can share information by reflecting signals that have been transmitted to it.
“The fundamental assumption people have made so far is that backscatter can be used only for low-data rate sensors such as temperature sensors,” says paper coauthor Shyam Gollakota, an associate professor in the University of Washington’s Paul G. Allen School of Computer Science & Engineering. “This work breaks that assumption and shows that backscatter can indeed support even full HD video.”
“There could be tiny HD cameras everywhere recording the action: stuck on players’ helmets, everywhere across the stadium. And you don’t have to ever worry about changing their batteries.”
In today’s streaming cameras, the camera first processes and compresses the video before it is transmitted via Wi-Fi. These processing and communication components eat a lot of power, especially with HD videos. As a result, a lightweight streaming camera that doesn’t need large batteries or a power source has been out of reach.
The team developed a new system that eliminates all of these components. Instead, the pixels in the camera directly connect to the antenna, which sends intensity values via backscatter to a nearby smartphone. The phone, which doesn’t have the same size and weight restrictions as a small streaming camera, processes the video instead.
For the video transmission, the system translates the pixel information from each frame into a series of pulses where the width of each pulse represents a pixel value. The time duration of the pulse is proportional to the brightness of the pixel.
“It’s sort of similar to how the cells in the brain communicate with each other,” says coauthor Joshua Smith, a professor in the Allen School and the University of Washington’s electrical engineering department. “Neurons are either signaling or they’re not, so the information is encoded in the timing of their action potentials.”
The team tested their idea using a prototype that converted HD YouTube videos into raw pixel data. Then they fed the pixels into their backscatter system. Their design could stream 720p HD videos at 10 frames per second to a device up to 14 feet away.
“That’s like a camera recording a scene and sending the video to a device in the next room,” says coauthor and computer science and engineering doctoral student Mehrdad Hessar.
Seeing the future in HD
The group’s system uses 1,000 to 10,000 times less power than current streaming technology. But it still has a small battery that supports continuous operation. The next step is to make wireless video cameras that are completely battery-free, says Smith.
The team has also created a low-resolution, low-power security camera, which can stream at 13 frames per second. This falls in line with the range of functions the group predicts for this technology.
“There are many applications,” says coauthor and recent electrical engineering alum Saman Naderiparizi. “Right now home security cameras have to be plugged in all the time. But with our technology, we can effectively cut the cord for wireless streaming cameras.”
The group also envisions a world where these cameras are smart enough to only turn on when they are needed for their specific purpose, which could save even more energy.
“This video technology has the potential to transform the industry as we know it. Cameras are critical for a number of internet-connected applications, but so far they have been constrained by their power consumption,” he says.
Why consumers may regret all this free streaming
“Just imagine you go to a football game five years from now,” Smith adds. “There could be tiny HD cameras everywhere recording the action: stuck on players’ helmets, everywhere across the stadium. And you don’t have to ever worry about changing their batteries.”
The team presented their findings April 10 at the Advanced Computing Systems Association’s Symposium on Networked Systems Design and Implementation.
The researchers have licensed the technology to Jeeva Wireless, a Seattle-based startup a team of university researchers founded, including Gollakota, Smith, and Vamsi Talla, a recent alum and coauthor of this paper.
The National Science Foundation, the Alfred P. Sloan Foundation, and Google Faculty Research Awards funded the research.
Source: Sarah McQuate for University of Washington
