Logo EPFL
I&C
 Ecole Polytechnique Fédérale de Lausanne
     Research
 English only       EPFL > I&C > CVLAB > Research > Detect > Ldahash
 RESEARCH
 Research Areas
Ph.D. Theses
 CVLAB CONTENTS
 People
Research
Publications
Teaching
Student projects
Software
Data
Jobs
Intranet
 QUICK LINKS
 EPFL Infoscience
I&C Doctoral School

Dynamic and Scalable Large Scale Image Reconstruction

SIFT-like local feature descriptors are ubiquitously employed in such computer vision applications as content-based retrieval, video analysis, copy detection, object recognition, photo-tourism and 3D reconstruction.
Feature descriptors can be designed to be invariant to certain classes of photometric and geometric transformations, in particular, affine and intensity scale transformations. However, real transformations that an image can undergo can only be approximately modeled in this way, and thus most descriptors are only approximately invariant in practice.
Secondly, descriptors are usually high-dimensional (e.g. SIFT is represented as a 128-dimensional vector). In large-scale retrieval and matching problems, this can pose challenges in storing and retrieving descriptor data.
We map the descriptor vectors into the Hamming space, in which the Hamming metric is used to compare the resulting representations.
This way, we reduce the size of the descriptors by representing them as short binary strings and learn descriptor invariance from examples.
We show extensive experimental validation, demonstrating the advantage of the proposed approach.

The training and evaluation data was obtained by using our calibration pipline Dynamic and Scalable Large Scale Image Reconstruction. Further evaluation was done on Lidar ground truth data as obtained by On Benchmarking Camera Calibration and Multi-View Stereo for High Resolution Imagery.


Results | Examples | Data | Software | References | Contact

Results


We trained our binray descriptor on the Lausanne database.

Venice internet image evaluation dataset: example patches corresponding to the same 3D point.

click to enlarge click to enlarge

Confusion matrix for the 24 largest tracks for the Venice dataset.

SIFT L2 norm LDAHash Hamming distance
click to enlarge click to enlarge

Calibration results using the binary descriptors


Lausanne cathedral statue

Sequence contains 127 18-Megapixel images of a statue at different scales.

result of the calibration: camera positions and sparse 3D points result of the calibration: 3D points (zoom)
click to enlarge click to enlarge

Data set courtesy of M.Pauly.
download
images corrected for radial distortion [gz] for the original images, please contact christoph strecha
calibration: projection matrices [gz]


Lausanne cathedral side entry

Sequence contains 288 18-Megapixel images of the Lausanne cathedral side entry at different scales.

result of the calibration: camera positions and sparse 3D points result of the calibration: 3D points (zoom)
click to enlarge click to enlarge

Data set courtesy of M.Pauly.
download
images corrected for radial distortion [gz] for the original images, please contact christoph strecha
calibration: projection matrices [gz]


Venice

Sequence contains internet images of Venice at different scales and sizes.

result of the calibration: camera positions and sparse 3D points result of the calibration: 3D points (zoom)
click to enlarge click to enlarge

Data

We will be sharing the training data sets here in future. Stay tuned.


Software

[c++ source ldahash2.0] available, please send an e-mail to christoph.strecha@cvlab.epfl.ch
[ldahash.1.0 source + keypoint evaluation] code
[ground truth eveluation data + source]


References

Main Reference


LDAHash: Improved matching with smaller descriptors

Christoph Strecha, Alex M. Bronstein, Michael M. Bronstein, Pascal Fua
IEEE Transactions on Pattern Analysis and Machine Intelligence
Under Review
Submitted August 2010


LDAHash: Improved matching with smaller descriptors

Christoph Strecha, Alex M. Bronstein, Michael M. Bronstein, Pascal Fua
Techical Report
pdf |

Related References


Dynamic and Scalable Large Scale Image Reconstruction

C. Strecha, T. Pylvanainen, P. Fua
CVPR 2010
website | pdf |


On Benchmarking Camera Calibration and Multi-View Stereo for High Resolution Imagery

C. Strecha, W. von Hansen, L. Van Gool, P. Fua, U. Thoennessen
CVPR 2010
website | pdf |


Efficient Large Scale Multi-View Stereo for Ultra High Resolution Image Sets

Engin Tola, Christoph Strecha, Pascal Fua
Machine Vision and Applications
Under Review
Submitted September 2010
website



Contact

Christoph Strecha [URL] [e-mail]
Alexander M. Bronstein [URL] [e-mail]
Michael M. Bronstein [URL] [e-mail]
Pascal Fua [URL] [e-mail]


Comments/Feedback to webmaster.cvlab { at } epfl.ch
Last update : 01 July 2011 08:23:48