KDDI Handset Uses Arm Swing Motion for Personal Authentication

Apr 14, 2009
Yukiko Kanoh, Nikkei Electronics
The structure and appearance of the prototype
The structure and appearance of the prototype
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The three-axial acceleration signals output by vertically swinging the mobile phone five times
The three-axial acceleration signals output by vertically swinging the mobile phone five times
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Images of a swinging action
Images of a swinging action
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KDDI R&D Laboratories Inc developed a system that can authenticate individuals by the way they swing a mobile phone embedded with an acceleration sensor (the arm swing authentication system).

The new system, which was developed jointly with Yoshinori Hatori Laboratory at the Tokyo Institute of Technology, retrieves signals from the acceleration sensor during arm swinging motion and judges the degree of similarity to a pre-registered swinging pattern.

A variety of individual characteristics, including physical characteristics including the length of an arm and muscle structure as well as action patterns such as holding methods and other habits, are reflected in the acceleration signals recorded during arm swinging motion, according to KDDI R&D Laboratories.

In addition, it is easy for a person to reproduce his/her own arm swing pattern, while it was confirmed that arm swing patterns are a physical characteristic that is difficult for someone else to reproduce even if the person happens to steal a look at the pattern, according to the company. Therefore, if an arm swing pattern known only to the user is used, it is possible to realize as accurate an authentication system as existing biometric authentication technologies.

The equal error rate, where an error rate of rejecting an authorized user and that of accepting a different person are equal, is 4% when arm swing patterns are disclosed. When action patterns are not disclosed, the equal error rate becomes even lower, according to the company.

The processing load for the authentication process is well within the level that a mobile phone can handle. The problem of instability that occurs until a certain pattern is learned and variations in the pattern over time will be solved by updating the template. The template update function modifies the registered action pattern by reflecting the latest pattern.

With the new authentication system, it will become possible to lock a personal folder in a handset by a secret action, and applications can be started by a special action pattern of the handset owner, the company said.

KDDI R&D Laboratories and its partner will enhance the maneuverability of the system by field experiments.