Fingerprint three-dimensional shape measurement system based on small field of view structured light

To address issues with traditional 2D fingerprint acquisition technology, such as distortion and hygiene risks, a structured light 3D measurement system for high-precision fingerprint topography measurement was introduced. By optimizing the phase calculation, telecentric imaging 3D detection model, and fast calibration algorithms, the problems of low accuracy and complex calibration of small field of view 3D measurement system could be solved. A 3D fingerprint acquisition system was built in the experiment, achieving the collection of fingerprints and the measurement of 3D morphology. Under the conditions of a field of view of 39.9 mm×26.6 mm at a working distance of 138 mm, the measurement accuracy of the system reaches 30 μm. Compared with traditional methods, the errors are significantly reduced, and the fingerprint collection speed is better than 1.5 s. The relevant research work is conducive to solving the problems of high acquisition cost and low reconstruction accuracy of 3D fingerprints, providing technical support for further improving the measurement accuracy, recognition rate and real-time detection performance of fingerprints in police physical evidence examination and trace examination and identification.