  In this paper, we propose a novel projector-camera system for practical and
low-cost acquisition of a dense object 3D model with the spectral reflectance
property. In our system, we use a standard RGB camera and leverage an
off-the-shelf projector as active illumination for both the 3D reconstruction
and the spectral reflectance estimation. We first reconstruct the 3D points
while estimating the poses of the camera and the projector, which are
alternately moved around the object, by combining multi-view structured light
and structure-from-motion (SfM) techniques. We then exploit the projector for
multispectral imaging and estimate the spectral reflectance of each 3D point
based on a novel spectral reflectance estimation model considering the
geometric relationship between the reconstructed 3D points and the estimated
projector positions. Experimental results on several real objects demonstrate
that our system can precisely acquire a dense 3D model with the full spectral
reflectance property using off-the-shelf devices.
