Oct 20, 2017: Today a high-quality camera in a smartphone is common, enforcing “no photography” rules for copyright or privacy reasons has become impossible. Researchers at the University of California San Diego and the University of Wisconsin-Madison are making efforts to solve this problem with a new project. They have created a smart LED system, which produces a flickering pattern that interferes with the camera sensor on mobile devices.
The researchers have developed LiShield, a smart LED light shield, which stops illegal photography of sensitive physical objects like people, documents, museum art, or sensitive places. It, therefore, automatically enforces the visual privacy protection without any user intervention. The system enables illumination of the environment with an eye-transparent light waveform, and the captured images or video are distorted because of the camera’s rolling shutter mechanism.
This new LED solution has a flickering pattern, which is invisible to the human eye, as it takes place at a high frequency, and wreaks havoc on a phone’s camera sensor.
The researchers have also found a way to let authorized users recover the image or video by sending waveform information about the light’s flickering pattern to the mobile device so that the two can sync together. It can also be done by piecing together several frames of video to create a still image. The LED can also generate structured light to embed an invisible watermark, which can then be detected after the fact by online servers to prevent illegal distribution.
The technology works only with a single LED and a small indoor space. In the future, the researchers would explore methods of using multiple smart LEDs to cover a much larger area. They are also developing a way to enhance the protection so that the system can be used in applications which require high security, such as the military.