System and method for 3D imaging using structured light illumination

Summary

Another continuation in the contactless 3D handprint family. The core remains the same — project structured light, capture the deformed pattern from several angles, reconstruct the 3D hand, and unwrap it into the flat rolled-print image that legacy databases expect — but this patent claims the camera-and-calibration arrangement that makes a single shot capture every surface a rolled inked print would.

On the hardware side, it covers a five-camera array surrounding the projector with overlapping fields of view, plus colored mirrors and wavelength-selective filters that fold thumb and side-of-finger surfaces back into the same shot the front-facing cameras see. Hand-positioning pegs guide the subject into the working volume, and a backdrop printed with a pseudo-random fine pattern, fiducial marks, and white calibration patches sits behind the hand in every frame.

On the processing side, the patent claims a per-scan recalibration that reads the known backdrop coordinates out of the captured image and retunes the geometry on the fly — so the system stays accurate without periodic factory service. It pairs that with color-encoded multi-frequency phase-measuring profilometry that separates overall hand shape from ridge-level detail in a single capture, and with a partitioned pipeline that crops the image into finger, thumb, and palm regions, processes each independently, then stitches the results back together by matching the backdrop pattern across pieces. The output is a standards-compliant rolled-equivalent print produced in seconds.