@inproceedings{agr-che-ras-05-algrec,
  title = {An Algebraic Approach to Surface Reconstruction from Gradient Fields},
  author = {Amit Agrawal and Rama Chellappa and Ramesh Raskar},
  booktitle = {Proc. 2005 International Conference on Computer Vision (ICCV)},
  year = 2005,
  pages = {174--181},
  doi = {10.1109/CVPRW.2009.5206603},
  comment = {Discusses the reconstructibility, curl, projection on curl-free space. Defines the alpha-surface method (although not with that name). Poor results.}
}