![]() The current LiShield prototype relies upon custom-built smart LED hardware and software algorithms used to control both the defensive flickering patterns and synchronization with an authorized camera. For capturing still images, the smart LED synchronizes with the authorized camera to help reconstruct a still image taken from several complementary frames in a very short video. That allows the smart LED to send recoverable waveform information about the flickering pattern in use during the authorized camera’s operation. For capturing video, authorized camera must use secure side channels to communicate its exposure time setting and synchronize its clock with the smart LED’s clock. LiShield can also allow specific “authorized users” to use their smartphones or digital cameras. student in computer science at the University of California San Diego and co-primary author on the paper. “We have to use the visible light spectrum for safety reasons.” “Strong infrared light can saturate the camera and block it from capturing images, but that infrared light would burn human eye retinas,” says Shilin Zhu, a Ph.D. LiShield’s capability to corrupt digital camera images and videos without interfering with human eyesight is an advantage over some past attempts to enable similar privacy protection. This is what makes the LiShield’s flickering patterns so effective. And while human eyes have the capacity to perceive very different levels of brightness across a dynamic range within the same scene, cameras tend to suffer from the overexposure or underexposure problems when exposed to lighting with vastly different intensities within the same scene. Such a privacy system is imperceptible to human eyes because it uses high-frequency flickering patterns beyond the limits of human eye sensitivity at around 80 Hertz. That creates the striped patterning in the captured images or video frames to ruin the overall photo or video. The on-off flickering patterns of the LiShield system ensure that some rows of pixels are overexposed and appear bright while other rows are underexposed and appear dark. Zhang and his colleagues presented their research on the first day of the ACM Mobicom 2017 conference held from 16-20 October at the Snowbird Ski Resort near Salt Lake City.ĭigital cameras use a rolling shutter sampling approach to capture images by exposing each row of pixels in sequence. The “LiShield” privacy system specifically targets consumer digital cameras such as smartphone-grade cameras by exploiting their limitations in capturing images. “Previously, when you are in locations like gyms or exam rooms or trade shows, in those locations the cameras are forbidden but there was no way to enforce the compliance,” says Xinyu Zhang, assistant professor in electrical and computer engineering at the University of California San Diego. “Our main achievement with LiShield is automating digital privacy.” It’s a first step toward enabling a cloak of privacy to be thrown over live events or exhibits, even in the presence of dozens of smartphones. Such flickering creates a vertical striped pattern effect in the photo or video frames taken by digital smartphone cameras without interfering with human eyesight or harming human eyes. The prototype privacy measure uses a smart LED to give off a high-frequency flickering pattern that interferes with the camera sensors on mobile devices such as smartphones. ![]() But a new indoor privacy system has shown how the power of smart LED lighting could prevent people from taking illegal videos of a live Broadway show or surreptitiously snapping photos during a secretive trade show presentation. Rules that prohibit photos or videos can prove almost impossible to enforce when nearly everyone carries a smartphone.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |