At airports, border crossings, and hospitals, iris recognition systems are gaining wider use. But they tend to be fixed and clunky, requiring people to stand in specific spots so that wall-mounted cameras can scan their irises. At the Chinese Academy of Sciences' Institute for Automation in Beijing, China, electrical engineer Tieniu Tan's group has developed a portable system that could enable security guards to scan people in line; it could also provide cell phones and other mobile devices with built-in authentication systems. Tan's handheld scanner uses near-infrared light to illuminate the eye, while an embedded camera captures images of the iris. Using speech synthesis software, the handheld can even tell the subject to move closer or farther away as needed. Novel image-processing algorithms select the clearest iris image-one that's in focus and unblocked by eyelashes-and analyze its tiny freckly patterns. Tests show the system is more than 99 percent accurate-as good as today's best stationary models. Some of the software runs on a desktop computer, but Tan is developing a completely portable system through a Beijing-based startup, Pattek. Its first application: authenticating users who log onto laptops, handhelds, and ATM machines.