FEBRUARY 27--Airport check-in may change if UK trials of a new type of split-second 3-D face imaging system are successful. The technology, being developed at Sheffield Hallam University's Materials and Engineering Research Institute (MERI; www.shu.ac.uk) by a team led by Prof. Marcos Rodrigues, passes a single pattern of light over the face creating a 2-D image from which 3-D data are generated. A 'parameterisation' process, providing an accurate digital map of the face, then extracts biometric features.
Other 3-D systems, requiring 16 shots of the face, have proved unworkable because of the time it takes to construct a picture. The chance of movement during such a multishot process is extremely high, and if the face moves even a fraction then the 2-D to 3-D image is unworkable.
MERI also claims several other advantages for its technology. Hardware requirements are a projector and a single camera, making setup inexpensive--a few hundred pounds, compared with up to £40,000 for older systems. These need at least three or four cameras to capture an image, which means time-consuming parameters and complex calibrations.
Traditional 2-D methods measure the distance between eyes, nose, and lips, taking several distance measurements and then comparing them. This works well if you can control everything, particularly illumination and movement. The MERI system takes 'real' measurements, such as the distance over the surface of the face rather than from one line to another. This makes the technology more robust and enables it to extract 40-100 parameters rather than the six that the older systems needed.
Possibly the most dramatic breakthrough is the speed at which the light passes over the face--just 40 ms--an innovation that enables a high throughput of 3-D face imaging. The system could be used like a metal detector, capturing a number of images in 3 or 4 s as a person walks through. The best image will be chosen automatically. The speed of the process will open up new applications in security and authorization.
Another third dimension that MERI wants to explore is utilizing the system in industrial applications for monitoring and control. 'Objects can go on a conveyor belt, and, instead of using a flat image, a 3-D image can help locate defects in them. "Although we are focusing on security applications now, there is great potential in the future," said Rodrigues.