System and method for 3D imaging using structured light illumination

Summary

Another continuation in the contactless 3D handprint family. The core remains the same — projected structured light, multi-angle capture, 3D-to-2D unrolling into the rolled-fingerprint format that legacy databases require — but this patent claims a different cross-section of the practical system.

On the user-facing side, it covers the hand-positioning pegs and the preview mode that guide the subject before the real capture, plus the mirror-and-color-filter arrangement that wraps a single shot around to the thumb and side surfaces the cameras would otherwise miss.

On the imaging side, it claims dual-frequency phase-measuring profilometry tuned for biometrics — a base frequency that captures overall hand shape and a high frequency that resolves ridges and pores — along with albedo compensation that removes skin- color variation, and an integrated-backdrop calibration that re-tunes the scanner on every capture. Together these turn the underlying scanning technique into a contactless biometric booth that holds its accuracy in routine deployment.