@inproceedings{woo-89-phocurv,
  author = {Robert J. Woodham},
  title = {Determining Surface Curvature with Photometric Stereo},
  booktitle = {Proceedings of the 1989 IEEE International Conference on Robotics and Automation},
  volume = {1},
  pages = {36--42},
  year = 1989,
  month = may,
  altkeys = {ieee-1989}
}