A Coaxial Optical Scanner for Synchronous Acquisition of 3D Geometry and Surface Reflectance

摘要

We present a novel optical setup and processing pipeline for measuringrnthe 3D geometry and spatially-varying surface reflectance ofrnphysical objects. Central to our design is a digital camera and arnhigh frequency spatially-modulated light source aligned to share arncommon focal point and optical axis. Pairs of such devices allowrncapturing a sequence of images from which precise measurementsrnof geometry and reflectance can be recovered. Our approach is enabledrnby two technical contributions: a new active multiview stereornalgorithm and an analysis of light descattering that has importantrnimplications for image-based reflectometry. We show that the geometryrnmeasured by our scanner is accurate to within 50 microns atrna resolution of roughly 200 microns and that the reflectance agreesrnwith reference data to within 5:5%. Additionally, we present an imagernrelighting application and show renderings that agree very wellrnwith reference images at light and view positions far from those thatrnwere initially measured.