The Rapid Touchless 3D Fingerprint Imaging Based on Full-field Microscopic Fringe Projection Technique

Abstract

Accurate three-dimensional (3D) fingerprint imaging is essential for next-generation biometric systems requiring high spatial resolution and microfeature fidelity. This study presents a novel, rapid, non-contact 3D fingerprint imaging system that integrates a seven-step phase-shifting fringe projection technique with a microscope-based optical configuration and structured RGB illumination. The system achieves lateral resolution better than 40 µm and vertical resolution below 5 µm, enabling precise reconstruction of ridge-valley structures and third-level features, such as sweat pores and ridge-edge contours. A comparative analysis of illumination wavelengths shows that green light provides the highest measurement accuracy, yielding a wrapped-phase standard deviation of 0.07 rad, a signal-to-noise ratio (SNR) exceeding 25 dB, and a root mean square error of 1.8 pixels in the unwrapped phase. Surface profiling results confirm the system’s capability to resolve ridge heights in the range of 45-65 µm and pore diameters between 80-150 µm. Compared to existing techniques, the proposed method offers enhanced spatial resolution, improved preservation of fine surface features, and a novel assessment of spectral effects on 3D reconstruction performance. With an acquisition time of less than one second, this system demonstrates a strong potential for applications in high-security biometric authentication, forensic investigation, and spoof-resistant technologies. Future research will focus on enabling real-time data processing, system miniaturization, and improved performance under dynamic or uncontrolled environmental conditions.