Identification rates are reduced when the surface of the fingerprint input device is soiled or damaged by contact in conventional systems of fingerprint authentication for personal identification. We evaluated the possibility of noncontact fingerprint authentication to address these problems. A method of extracting the principal lines (valley lines) of a fingerprint from the color picture of a fingertip from non-contact visual input is proposed in this study as an approach to non-contact fingerprint authentication. First, an input image is decomposed into 10 subband images using the 2-D discrete wavelet trans-form three times. Next, the edge component is separated from high frequency subband images. Then, the principle lines are extracted from the combined Y and Z components of an XYZ color system. The experimental result revealed the usefulness of the proposed technique.
