@conference {311,
	title = {Return detection for outdoor active triangulation},
	booktitle = {SPIE 3D Image Processing (3DIP) and Applications },
	year = {2011},
	keywords = {laser cane},
	url = {http://users.soe.ucsc.edu/~manduchi/papers/SPIE2010Preprint.pdf},
	author = {David Ilstrup and Roberto Manduchi}
}
