Graph Cut with Ordering Constraints on Labels and its Applications

1. Graph Cut with Ordering Constraints on Labels and its Applications Xiaoqing Liu, Olga Veksler ,JagathSamarabandu University of Western Ontario London, Canada CVPR 2008

2. Outline • Introduction • Graph-Cut optimization • Order-Preserving Moves • Geometric Class Scene Labeling • Applications • Virtual Scene Walk-Through • Shape Prior for Segmentation

3. Introduction • Pixel labeling problems • assigning a label from a finite set of possibilities to each image pixel • Alpha-expansion • Graph-Cut optimization • An energy function on the labeling is minimized • Order-preserving moves • rule out improbable segmentations

4. Order-Preserving Moves • L, R, T , B, C • Left, right, top, bottom, center • To get to a better labeling, a smaller C region is needed • Labels B, T , L, and R need to expand • Order-preserving • horizontal order-preserving • vertical order-preserving

5. Order-Preserving Moves

6. Graph-Cut optimization • The energy function:

7. Graph-Cut optimization

8. Geometric Class Scene Labeling • Results • 600 images from different indoor • 84 outdoor street images • All images were manually labeled • We used half of the images for training and half for testing

12. Application 1 • Virtual Scene Walk-Through

13. Application 2 • Shape Prior for Segmentation