This is code accompanying the ICCV paper "Network Principles for SfM: Disambiguating Repeated Structures with Local Context". It is intended to be used as an add-on to a structure from motion pipeline such as bundler-sfm. Prior to reconstruction, this code takes a set of geometric constraints (tracks) and cleans them up, returning a second set which is hopefully free of the sorts of large errors caused by ambiguous scene objects.
All the code is written in Matlab. It should run out of the box, although see note 1 below. demo_sfmDisambiguation.m is the driver script, and contains variables to set up I/O paths according to your setup. As discussed in the paper, this method accepts one tracks file, and a file of image field of view information, and returns a new tracks file that is hopefully free from errors. The tracks file format is the same as that used in bundler, and is documented in util/readTracksFile.m
All code has been tested on Matlab R2011a- on other versions YMMV.
(1) The tracks file format doesn't play that well with Matlab, although it is very easy to read and write in C. In my own development I've used a mex'ed file writer which is included. To allow this code to run without toolboxes, I also incldued a pure-Matlab version in this code, but it is orders of magnitude slower- sometimes taking hours! If you have mex'ing abilities, do this: cd util mex writeTracksFile_mex.c
(2) The code for computing the bipartite local clustering coefficient will use multiple threads if a local matlabpool is open. If you have the parallel computing toolbox, set opt_useParallel=true in demo_sfmDisambiguation.m.
(3) This code is intended to be run as part of a structure from motion pipeline, where it recieves a set of tracks, cleans them, and passes them on to a geometric solver. However, in case it's useful, I've also included a few lines to extract the tracks out of an existing bundle file. This code isn't well optimized, so the file IO might take annoyingly long. To take input from a bundle file, change opt_tracksSource to 'bundlefile' in demo_sfmDisambiguation.m.
(4) This distribution is covered under a FreeBSD license. Please see the included license file for more details.
Please address comments or questions about the code to: Kyle Wilson, wilsonkl (at) cs.cornell.edu
Here is the bibTeX reference: @inproceedings{wilson_iccv2013_disambig, Title = {Network Principles for SfM: Disambiguating Repeated Structures with Local Context} Author = {Kyle Wilson and Noah Snavely}, booktitle = {Proceedings of the International Conference on Computer Vision ({ICCV})}, Year = {2013}, }