Advanced Technologies for Touchless Fingerprint Recognition

Abstract

A fingerprint capture consists of touching or rolling a finger onto a rigid sensing surface. During this act, the elastic skin of the finger deforms. The quantity and direction of the pressure applied by the user, the skin conditions, and the projection of an irregular 3D object (the finger) onto a 2D flat plane introduce distortions, noise, and inconsistencies on the captured fingerprint image. Due to these negative effects, the representation of the same fingerprint changes every time the finger is placed on the sensor platen, increasing the complexity of the fingerprint matching and representing a negative influence on the system performance. Recently, a new approach to capture fingerprints has been proposed. This approach, referred to as touchless or contactless fingerprinting, tries to overcome the above-cited problems. Because of the lack of contact between the finger and any rigid surface, the skin does not deform during the capture and the repeatability of the measure is quiet ensured. However, this technology introduces new challenges. Finger positioning, illumination, image contrast adjustment, data format compatibility, and user convenience are key in the design and development of touchless fingerprint systems. In addition, vulnerability to spoofing attacks of some touchless fingerprint systems must be addressed.