Wide-field 3D imaging with an LED pattern projector for accurate skin feature measurements via Fourier transform profilometry

Abstract

Accurate 3D imaging of human skin features with structured light methods is hindered by subsurface scattering, the presence of hairs and patient movement. In this work, we propose a wide-field 3D imaging system capable of reconstructing large areas, e.g. the whole surface of the forearm, with an axial accuracy in the order of 10 microns for measuring scattered skin features, like lesions. By pushing the limits of grating projection we obtain high-quality fringes within a limited depth of field. We use a second projector for accurate positioning of the object. With two or more cameras we achieve independent 3D reconstructions automatically merged in a global coordinate system. With the positioning strategy, we acquire two consecutive images for absolute phase retrieval using Fourier Transform Profilometry to ensure accurate phase-to-height mapping. Encouraging experimental results show that the system is able to measure precisely skin features scattered in a large area. Copyright © 2019 SPIE.