@techreport{Chen2011_0,
        Abstract = {In this report we will present a practical working pipeline for building a BRDF database of art painting. We use the MCSL Imaging Goniospectrometer collect BRDF measurements for 24 panels, each of which consists 25 different patches. For each patch on each panel, we recover the diffuse surface normals using photometric stereo method and fit the data using analytic BRDF models, such as Ward and Cook-Torrance BRDF models. One of the main contributions of this work is to use the specular normal for BRDF fitting instead of using diffuse normal. The improvement is significant when the sample is glossy. We will also describe in detail how to efficiently fit the BRDF data using non-linear constrained Levenberg-Marquardt optimization method. We reconstructed BRDFs for the 24 panels and will show several example results.},
        Address = {Rochester, New York, United States},
        Author = {Tongbo Chen and Lawrence A. Taplin and Roy S. Berns},
        Institution = {Rochester Institute of Technology, College of Science, Center for Imaging Science,Munsell Color Science Laboratory},
        Keywords = {Art-SI; Art-Si-3D Imaging},
        Month = {March},
        Number = {},
        Title = {Artist Material Database BRDF Fitting},
        Url = {http://www.cis.rit.edu/DocumentLibrary/admin/uploads/CIS000122.pdf},
        Year = {2011}}