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

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.