Optics Letters

We propose encrypted fringe projection profilometry (E-FPP), a co-keyed phasecode framework that embeds encryption directly into the measurement process of fringe projection profilometry (FPP). Two random phase fields and orthogonal temporal codes jointly encode the projected sequence, binding phase retrieval to legitimate key pairs. The method preserves standard three-step FPP operation while enabling key-dependent 3D reconstruction. Experiments verify accurate authorized reconstruction and strong resistance to single- and multi-frame inference, providing a privacy-preserving solution for optical metrology.