1. 3D Visual Phrases for Landmark Recognition
Qiang Hao, Rui Cai, Zhiwei Li, Lei Zhang, Yanwei Pang, Feng Wu
Tianjin University, Tianjin , P.R. China
Microsoft Research Asia, Beijing , P.R. China

2. Outline Introduction 3D Visual Phrase Discovery
3D Visual Phrase Description
3D Visual Phrase Detection
Evaluation
Conclusion and Future Work

3. Introduction Most existing work(BoW)
features extracted from irrelevant objects
treats the database images independently
A 3D visual phrase is a triangular facet on the surface of a reconstructed 3D landmark model.
explicitly characterize the spatial structure of a 3D object
highly robust to projective transformations due to viewpoint changes.

4. Introduction

5. 3D Visual Phrase Discovery
3D Landmark Reconstruction
3D Point Selection
3D Visual Phrase Generation
Multi-Scale 3D Visual Phrases

6. 3D Visual Phrase Discovery

7. Multi-Scale 3D Visual Phrases

8. 3D Visual Phrase Description
Visual Appearance
Geometric Structure

9. Visual Appearance

10. Geometric Structure

11. 3D Visual Phrase Detection
Appearance-based Point Matching
Geometry-based Intra-Phrase Ranking
Graph-based Inter-Phrase Refinement

12. 3D Visual Phrase Detection

13. Evaluation

14. Evaluation

15. Evaluation

16. Evaluation

17. Conclusion and Future Work
In contrast to 2D visual phrases defined in 2D image planes, 3D visual phrases are derived from the physical space and explicitly characterize the 3D spatial structure of a landmark
Highly robust to viewpoint changes.
Geometric constraintsare desired to afford to more relaxed point matching
Accelerate the algorithms, especially the point matching step.

18. Thank you for listening