Fingerprint Authentication Device Based on Optical Characteristics Inside a Finger

Fingerprint is the most popular modality that is widely used in various authentication applications; PC logon, gate access control systems, and so on. The reason can be considered that fingerprint can achieve the best balance among authentication performance, cost, size of device, and ease of use. However, most of fingerprint authentication devices have some problems to be solved. One is that captured images are easily affected by the condition of finger surface and it can degrade authentication performance. The other is that the problem of impersonation by artificial gummy fingers has been pointed out. To solve those problems, we developed a new fingerprint authentication device that has a novel sensing principle. This device forms a image of fingerprint pattern based on optical characteristics of a finger’s interior by scattered transmission light. The images so obtained are unaffected by the condition of finger surface such as dry or moist fingers or operating environment, and enable stable authentication processes. And it can differentiate between real fingers and fake gummy fingers made from gelatin or other material using optical characteristics. Because this device utilizes the optical characteristics inside a finger, it has possibility to achieve higher authentication performance by combining multiple characteristics of a finger’s interior as a modality. In this paper, we describe the sensing principle and process algorithm of this device.