Optical fibers replace lenses.
Source: “Exploiting Collective Effects of Multiple Optoelectronic Devices Integrated in a Single Fiber”
Yoel Fink et al.
Nano Letters 9: 2630-2635
Results: Researchers at MIT have found a way to take photographs with polyester fibers. They integrated eight photodetectors into the fibers, arranged the fibers into a 32-by-32 grid spread over an area the size of a record album, and used the grid to capture a black-and-white image of a smiley face.
Why it matters: A standard camera requires lenses, which are rigid and fragile and can be heavy. A camera made from fibers, however, could be foldable, durable, and lightweight. In one potential application, it could be integrated into soldiers’ uniforms to create images of the surrounding environment.
Methods: Lenses focus scattered light to form an image. In the absence of a lens, measurements of the intensity of the scattered light can be used to computationally derive an image. To “photograph” the smiley face, the researchers illuminated it with laser light at different wavelengths, green and red. The photodetectors, embedded in a ring within each fiber, were able to distinguish light from each laser. After measuring the relative intensity of the colors, the researchers were able to apply algorithms that calculated the phase of the lightwaves scattered by the face. A separate algorithm used the phase information to reconstruct the image.
Next steps: The researchers plan to add more sensors to the fibers so that they can make images of objects illuminated with natural light. This could also lead to a color camera.
A new approach reliably identifies fraudulent websites.
Source: “Fighting Phishing with Discriminative Keypoint Features”
Kuan-Ta Chen et al.
IEEE Journal of Internet Computing 13(3): 56-63
Results: Software designed by researchers at the Academia Sinica in Taiwan can recognize websites designed to trick people into revealing information such as passwords and bank-account numbers, a scam known as phishing. In tests, the system recognized these sites between 95 and 98 percent of the time.
Why it matters: It’s been estimated that phishing costs Americans a billion dollars a year or more. Methods for identifying phishing sites have been developed, but existing techniques don’t catch them all. The new approach promises to identify these sites more reliably.
Methods: Because phishers usually try to fool users with fake Web pages that look like genuine pages from eBay, PayPal, or some other target site, the researchers focused on a page’s appearance rather than its content. Their system examines common target sites and identifies “keypoints”–points in an image that can still be recognized even if the scammer changes colors or adds distracting elements. It then compares new sites that a user visits with the pattern of keypoints on common target pages. If the patterns prove too similar, the pages are flagged as possible phishing sites.
Next steps: The researchers are developing a browser plug-in that uses their system to warn people when they may have reached a phishing site.