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ACM SIGGRAPH 2022 (Transactions on Graphics)

Sparse Ellipsometry: Portable Acquisition of Polarimetric SVBRDF
and Shape with Unstructured Flash Photography
  Inseung Hwang   Daniel S. Jeon   Adolfo Muñoz  
  Diego Gutierrez   Xin Tong   Min H. Kim  
  KAIST Microsoft Research Asia   Universidad de Zaragoza - I3A
SIGGRAPH Technical Paper Award Honorable Mention
  We propose the first sparse ellipsometry method that simultaneously captures both the polarimetric SVBRDF (including the 3D Mueller matrix and the index of refraction) and the 3D shape of real-world objects. Different from traditional ellipsometry, our portable acquisition device is made up of off-the-shelf, fixed optical components. Our sparse observations can be captured in minutes instead of days, allowing for accurate renderings of novel views under different illuminations.  
  Fast forward video at ACM SIGGRAPH 2022  
  Presentation video at ACM SIGGRAPH 2022 (v.2)  
  Supplemental video results  

Ellipsometry techniques allow to measure polarization information of materials, requiring precise rotations of optical components with different configurations of lights and sensors. This results in cumbersome capture devices, carefully calibrated in lab conditions, and in very long acquisition times, usually in the order of a few days per object. Recent techniques allow to capture polarimetric spatially-varying reflectance information, but limited to a single view, or to cover all view directions, but limited to spherical objects made of a single homogeneous material.We present sparse ellipsometry, a portable polarimetric acquisition method that captures both polarimetric SVBRDF and 3D shape simultaneously. Our handheld device consists of off-the-shelf, fixed optical components. Instead of days, the total acquisition time varies between twenty and thirty minutes per object. We develop a complete polarimetric SVBRDF model that includes diffuse and specular components, as well as single scattering, and devise a novel polarimetric inverse rendering algorithm with data augmentation of specular reflection samples via generative modeling. Our results show a strong agreement with a recent ground-truth dataset of captured polarimetric BRDFs of real-world objects.

  author  = {Inseung Hwang and Daniel S. Jeon and Adolfo Muñoz and 
             Diego Gutierrez and Xin Tong and Min H. Kim},
  title   = {Sparse Ellipsometry: Portable Acquisition of Polarimetric
             SVBRDF and Shape with Unstructured Flash Photography},
  journal = {ACM Transactions on Graphics (Proc. SIGGRAPH 2022)},
  year    = {2022},
  volume  = {41},
  number  = {4},
  The original paper published in the ACM DL holds errata of Equations (17) and (26). Here we provide an author copy (v.2) where the equation errata are corrected. Note that these errara were introduced only in the paper when writing up. The originally deployed codes from GitHub are correct and do not need any correction.
Preprint paper:
PDF v.2 (9.7MB)
PDF (11.6MB)
SIGGRAPH 2022 slides v.2
PDF (10.7 MB)
www GitHub code &
www ACM
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