Friday, January 6, 2012

3 Technology Link

3 Technology Link

Clever math could enable a high-quality 3-D camera for cellphones

Posted: 06 Jan 2012 10:21 AM PST

Clever math could enable a high-quality 3-D camera for cellphones


Clever math could enable a high quality 3 D camera for cellphones

Depth-sensing cameras can produce 'depth maps' like this one, in which distances are depicted as shades on a gray-scale spectrum (lighter objects are closer, darker ones farther away). Image: flickr/Dominic


When Microsoft's Kinect — a device that lets Xbox users control games with physical gestures — hit the market, computer scientists immediately began hacking it. A black plastic bar about 11 inches wide with an infrared rangefinder and a camera built in, the Kinect produces a visual map of the scene before it, with information about the distance to individual objects. At MIT alone, researchers have used the Kinect to create a "Minority Report"-style computer interface, a navigation system for miniature robotic helicopters and a holographic-video transmitter, among other things.

Now imagine a device that provides more-accurate depth information than the Kinect, has a greater range and works under all lighting conditions — but is so small, cheap and power-efficient that it could be incorporated into a cellphone at very little extra cost. That's the promise of recent work by Vivek Goyal, the Esther and Harold E. Edgerton Associate Professor of Electrical Engineering, and his group at MIT's Research Lab of Electronics.

"3-D acquisition has become a really hot topic," Goyal says. "In consumer electronics, people are very interested in 3-D for immersive communication, but then they're also interested in 3-D for human-computer interaction."

Andrea Colaco, a graduate student at MIT's Media Lab and one of Goyal's co-authors on a paper that will be presented at the IEEE's International Conference on Acoustics, Speech, and Signal Processing in March, points out that gestural interfaces make it much easier for multiple people to interact with a computer at once — as in the dance games the Kinect has popularized.

"When you're talking about a single person and a machine, we've sort of optimized the way we do it," Colaco says. "But when it's a group, there's less flexibility."

Ahmed Kirmani, a graduate student in the Department of Electrical Engineering and Computer Science and another of the paper's authors, adds, "3-D displays are way ahead in terms of technology as compared to 3-D cameras. You have these very high-resolution 3-D displays that are available that run at real-time frame rates.

"Sensing is always hard," he says, "and rendering it is easy."

Clocking in

Like other sophisticated depth-sensing devices, the MIT researchers' system uses the "time of flight" of light particles to gauge depth: A pulse of infrared laser light is fired at a scene, and the camera measures the time it takes the light to return from objects at different distances.

Traditional time-of-flight systems use one of two approaches to build up a "depth map" of a scene. LIDAR (for light detection and ranging) uses a scanning laser beam that fires a series of pulses, each corresponding to a point in a grid, and separately measures their time of return. But that makes data acquisition slower, and it requires a mechanical system to continually redirect the laser. The alternative, employed by so-called time-of-flight cameras, is to illuminate the whole scene with laser pulses and use a bank of sensors to register the returned light. But sensors able to distinguish small groups of light particles — photons — are expensive: A typical time-of-flight camera costs thousands of dollars.

The MIT researchers' system, by contrast, uses only a single light detector — a one-pixel camera. But by using some clever mathematical tricks, it can get away with firing the laser a limited number of times.

The first trick is a common one in the field of compressed sensing: The light emitted by the laser passes through a series of randomly generated patterns of light and dark squares, like irregular checkerboards. Remarkably, this provides enough information that algorithms can reconstruct a two-dimensional visual image from the light intensities measured by a single pixel.

In experiments, the researchers found that the number of laser flashes — and, roughly, the number of checkerboard patterns — that they needed to build an adequate depth map was about 5 percent of the number of pixels in the final image. A LIDAR system, by contrast, would need to send out a separate laser pulse for every pixel.

To add the crucial third dimension to the depth map, the researchers use another technique, called parametric signal processing. Essentially, they assume that all of the surfaces in the scene, however they're oriented toward the camera, are flat planes. Although that's not strictly true, the mathematics of light bouncing off flat planes is much simpler than that of light bouncing off curved surfaces. The researchers' parametric algorithm fits the information about returning light to the flat-plane model that best fits it, creating a very accurate depth map from a minimum of visual information.

On the cheap

Indeed, the algorithm lets the researchers get away with relatively crude hardware. Their system measures the time of flight of photons using a cheap photodetector and an ordinary analog-to-digital converter — an off-the-shelf component already found in all cellphones. The sensor takes about 0.7 nanoseconds to register a change to its input.

That's enough time for light to travel 21 centimeters, Goyal says. "So for an interval of depth of 10 and a half centimeters — I'm dividing by two because light has to go back and forth — all the information is getting blurred together," he says. Because of the parametric algorithm, however, the researchers' system can distinguish objects that are only two millimeters apart in depth. "It doesn't look like you could possibly get so much information out of this signal when it's blurred together," Goyal says.

The researchers' algorithm is also simple enough to run on the type of processor ordinarily found in a smartphone. To interpret the data provided by the Kinect, by contrast, the Xbox requires the extra processing power of a graphics-processing unit, or GPU, a powerful special-purpose piece of hardware.

"This is a brand-new way of acquiring depth information," says Yue M. Lu, an assistant professor of electrical engineering at Harvard University. "It's a very clever way of getting this information." One obstacle to deployment of the system in a handheld device, Lu speculates, could be the difficulty of emitting light pulses of adequate intensity without draining the battery.

But the light intensity required to get accurate depth readings is proportional to the distance of the objects in the scene, Goyal explains, and the applications most likely to be useful on a portable device — such as gestural interfaces — deal with nearby objects. Moreover, he explains, the researchers' system makes an initial estimate of objects' distance and adjusts the intensity of subsequent light pulses accordingly.

The telecom giant Qualcomm, at any rate, sees enough promise in the technology that it selected a team consisting of Kirmani and Colaco as one of eight winners — out of 146 applicants from a select group of universities — of a $100,000 grant through its 2011 Innovation Fellowship program.


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Ramnit’s heist bags 45,000 Facebook passwords

Posted: 06 Jan 2012 10:09 AM PST

Ramnit’s heist bags 45,000 Facebook passwords


Ramnits heist bags 45,000 Facebook passwords

Number of Ramnit Infected Machines Between September 2011 and December 2011. Image: Seculert.


( — Ramnit, the bank-thieving worm, is at it again, this time scoffing up Facebook accounts. The latest oh-look-another-threat is one that security watchers say could get ugly. Ramnit has grown up since it was first discovered as a virus in the wild in 2010. Security company Seculert has posted a January 5 blog saying that Ramnit has stolen 45,000 Facebook login credentials. The accounts are mostly in the UK and France. The security firm, which has been tracking Ramnit, discovered the stolen Facebook cache in its Seculert labs. Seculert in turn passed on to Facebook the stolen credentials that it found on Ramnit servers.

Ramnit's command and control center is visible and accessible, and the security experts were able to determine the precise number of Facebook victims, which consisted of 69 percent from the UK, 27 percent from France and 4 percent from other countries.

When Ramnit first started causing mischief in 2010 it was considered as a low-level threat, comments

That assessment has changed. Ramnit's operators were able to graduate from an older generation of techniques to infect files to morph it into something more powerful, adding Zeus source code to the mix. Trusteer, another security company, warned that the worm had acquired the ability to inject HTML code into a web browser.

A worm is a type of malware that secretly integrates itself into program or data files, and infects more files each time the host program is run. Ramnit can infect Windows executable files, HTML files and other file types.

Ramnit's subsequent target was finance, bypassing two-factor authentication and transaction signing systems. In gaining remote access to financial institutions, Ramnit was able to compromise online banking sessions and was able to penetrate corporate networks.

Even before the latest Facebook heist, Seculert, using a sinkhole security tool, counted 800,000 machines as infected with Ramnit from September to the end of December 2011.

Ramnit's presence is not immediately obvious. The worrisome nature of Ramnit is compounded by the fact, say experts, that users tend to use the same password for a number of web-based services, which may include not only Facebook but their mail, a VPN, and others..

Blogger reactions to the news have ranged from "Change your passwords, and often!" to "Don't click any links, never, no matter from who or how interesting!"

Considering the very definition of social networks and why they are used, that kind of advice may be timely but curiously counter to the whole point. Suspecting friends and relatives of having virus-choked messages and afraid to share links for fear of infection run counter to the reason why users sign on to social networks. Behavioral trends and countertrends will get interesting too.

Another troubling sign of the times is what cybercriminals now see as choice game. E-mail worms are so Yesterday, say computer security experts.

Malware writers are replacing old-school worms transmitted via email with their malware now targeted for social-networks.

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Apple patent sends password secrets to adapters

Posted: 06 Jan 2012 09:48 AM PST

Apple patent sends password secrets to adapters


Apple patent sends password secrets to adapters

( — First-time computer users in the early days, pre-hacking security traumas, were confronted with a new life requirement: creating and remembering system passwords. Not too easy, users were warned, to protect their privacy against snooping brothers and sisters, but not too tough, so they can easily remember it all times. This is no longer good advice, and Apple has filed a patent that says, no, make your password as tough as you want.


The patent filed by Apple seeks to help users recover their passwordinformation with use of a charger peripheral that doubles as the user's security key for password recovery.

Apple says in the patent application, dated July 2010 and made public this month, that too often users choose to make their passwords simple, which just makes the work of thieves all that easier. Instead, Apple is suggesting that a user's MacBook or smartphone or any iOS device password recovery information could be stored inside its charging adapter.

The idea is to shift the security information to the adapter, in the event that the user's laptop or smartphone or tablet is stolen or otherwise missing. In so doing, the user can make it tough for thieves because the user can feel free to construct more complex password strings.

Once the user plugs in the peripheral, the recovery process for password retrieval and display is done.The patent application is titled, "System and Method for Storing a Password Recovery Secret," and the inventor is named as Guy Tribble, of Hillsborough, California. Apple is proposing that a small memory module built into the unit holds the password or recovery question.

For users really concerned about security complex enough to thwart thieves skilled in working out passwords, Apple suggests the user might want to use multiple peripherals as an alternative scenario, where the adapter could hold part of the information and the other could reside elsewhere, as on some remote network server.

The patent application's idea seems useful obviously in instances where one is travelling with the laptop or other mobile computing device but not the charger. Apple is assuming the user taking advantage of this password-retrieval approach leaves the charging device behind, at home or in some desk or locker, before going out on the road.

While many reactions have been favorable to the patent idea, others note that the assumption may be too easily drawn. Some laptop users always carry their chargers with them because of limited battery life, though tablets and smartphones last a long time. A heist that includes both charger and computer places the user out of luck, say some detractors, who also note that cyber thieves eventually will figure out password information on the charger too. Detractors also note that as soon as the time would come for such a device to go commercial, thieves would start seeking out such chargers as worthy for stealing.

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