In-situ and highly portable SVBRDF acquisition method
Abstract
Acquiring Spatially-Varying Bi-directional Reflectance Distribution Function (SVBRDF) of 3D objects is a very complex task due to high dimensionality of the measurement (i.e., light and view directions, but also the spatial variations). In this context, laboratory set-ups manage to obtain very accurate data thanks to precise calibrations in a controlled environment.
However, camera and light calibrations carried out in-situ are much more complex. Previous work is limited in angular distribution [1] or requires strong priors on the SVBRDF [2] or the shape [3] of the captured object. Moreover, in-situ constraints seem to show that a model driven approach may be better suited instead of data driven one [1]. This explains why creating a portable set-up for uncontrolled environments is really challenging.
We present a new highly portable acquisition method. It consists acquiring and reconstructing the shape, the SVBRDF and the normal map from two cameras and a light spot. In addition, we propose a novel fast light calibration method deployable in-situ, using two mirror balls. Our method has the advantage of being very size-scalable and adaptable in-situ. It is based on a rapid positioning for each light/view pair that allows great freedom of angular distribution without strong a priori.
We validate our method numerically on synthetic scenes and we also present results on real objects with complex reflectance and shape.
References
1.Nam, Lee et al., 2018, ACM Transactions on Graphics, https://doi.org/10.1145/3272127.3275017
2.Zhou et al., 2016, ACM Transactions on Graphics, https://doi.org/10.1145/2980179.2980247
3.Ren et al., 2011, ACM Transactions on Graphics, https://doi.org/10.1145/2010324.1964940