Retinal scans have a lot going for them as a form of identification. You can’t forget your retinas, they're unique, they’re a lot harder to steal than passwords, and Captain Kirk uses them. The problem is, the technology needed to run a reliable retinal scan is often bulky, expensive, and hard to use. Scientists at the Dresden-based Fraunhofer Institute for Photonic Microsystems (IPMS) have shrunk down retinal scanning technology in the hopes of making retinal scans a more widespread identification technology.
Retinal scans are based on the fact that the pattern of blood vessels in the eye’s retina are as individual as a fingerprint. However, they are currently limited as a general means of identification because the equipment tends to be on the expensive and immobile side. With their Mobile Authentication via Retina Scanner (MARS), Fraunhofer scientists have been able to reduce the size of the optical components required for a retinal scanning system so it is portable, thereby opening up the possibility of retinal scans one day being used to unlock mobile devices.
The MARS prototype is small and mobile, with the optical components (but currently not the electronics) needed to image the retina fitting in a unit ergonomically designed for the human hand that measures only about 650 cm³ (39 in³). According to Fraunhofer, it uses silicon-based microelectronic components that are as small as microchips, an optically-safe infrared laser, and a series of optics, including a Micro Electro Mechanical System (MEMS) scanning mirror. The laser scans the blood vessels, which stand out against the photoreceptor cells of the retina because they reflect less light. The blood vessels are mapped and the pattern compared with the pattern stored in an internal memory.
Aside from its compactness, another major selling point of MARS is that it’s a self-contained contained system that doesn't need to communicate with a remote server. "First, the scans remain on the device and do not land in a database," says Dr. Uwe Schelinski, group manager of Systems Integration at IPMS. "Second, I am more willing to scan myself with my own device than with a permanently installed third party system."
The MARS prototype is scheduled to be displayed at Optatec 2014, the international trade show for optical technologies in Frankfurt running from May 20 to 22. It’s currently being tested and Fraunhofer says it hopes to have the electronics integrated into a device only slightly larger than the prototype by the end of the year. It says the technology may one day form the basis for an integrated technology or one that can be used as a smartphone accessory.
"It’s still a long way until we can integrate the technology into a smartphone," says Schelinski. "Another possibility would also be small accessory modules that communicate with the smartphone via Bluetooth, NFC or WLAN. Perhaps that is also the more prudent option in the first stage, since smartphones are still too insecure."