Havran, VlastimilReinhard Klein and Holly Rushmeier2016-07-182016-07-182016978-3-03868-007-92309-5059https://doi.org/10.2312/mam.20161250https://diglib.eg.org:443/handle/10.2312/mam20161250We present our experiences with using an autocollimator to set up the surface reflectance measurement for both BRDF and BTF. Assuming the measured material appearance is put on a locally flat surface, the autocollimator allows us to set the perpendicularity of the measured sample in stationary measurement setups. The principle works also vice versa, we can align the measurement setup against a stationary sample for on-site measurements. The autocollimator requires to use a collimated beam of light, a mirror, a beam splitter, and a detector. We describe the autocollimator principle, problems, and the issues involved when using an autocollimator for surface reflectance measurement setups.I.3.7 [Computer Graphics]Three Dimensional Graphics and RealismColorshadingshadowingand textureI.4.1 [Image Processing and Computer Vision]Digitization and Image CaptureReflectance10.2312/mam.2016125015-18