1. GrabCut Interactive Foreground Extraction using Iterated Graph Cuts Carsten Rother Vladimir Kolmogorov Andrew Blake Microsoft Research Cambridge-UK

2. Problem Problem GrabCut – Interactive Foreground Extraction 2 Fast & Accurate ?

3. Graph Cuts modelling in images Graph Cuts modelling in images GrabCut – Interactive Foreground Extraction 5 Image Min Cut Min Cut Cut: separating source and sink; Energy: collection of edges Min Cut: Global minimal enegry in polynomial time Foreground (source) Background (sink)

4. Graph Cuts for foreground extraction Graph Cuts for foreground extraction GrabCut – Interactive Foreground Extraction 5 Min Cut Min Cut Foreground (source) Background (sink) Assume we know foreground is white and background is black

5. GrabCut – Interactive Foreground Extraction 5 Min Cut Min Cut Foreground (source) Background (sink) Assume we know foreground is white and background is black Data term = (cost of assigning label) Regularization = (cost of separating neighbors) Graph Cuts for foreground extraction Graph Cuts for foreground extraction

6. GrabCut – Interactive Foreground Extraction 5 Min Cut Min Cut Foreground (source) Background (sink) Assume we know foreground is white and background is black Data term = whiteness (cost of assigning label) Regularization = (cost of separating neighbors) Graph Cuts for foreground extraction Graph Cuts for foreground extraction

7. GrabCut – Interactive Foreground Extraction 5 Min Cut Min Cut Foreground (source) Background (sink) Assume we know foreground is white and background is black Data term = whiteness (cost of assigning label) Regularization = color match (cost of separating neighbors) Graph Cuts for foreground extraction Graph Cuts for foreground extraction

8. We are all set now ! We are all set now ! User Initialisation Learn foreground color model Graph cuts to infer the foreground ? GrabCut – Interactive Foreground Extraction 6

9. Iterated Graph Cuts Iterated Graph Cuts User Initialisation Learn foreground color model Graph cuts to infer the foreground ? GrabCut – Interactive Foreground Extraction 6

10. 1 2 34 Iterated Graph Cuts Iterated Graph Cuts GrabCut – Interactive Foreground Extraction 7 Energy after each IterationResult Guaranteed to converge

11. Moderately straightforward examples Moderately straightforward examples … GrabCut completes automatically GrabCut – Interactive Foreground Extraction 10

12. Difficult Examples Difficult Examples Camouflage & Low Contrast No telepathy Fine structure Initial Rectangle Initial Result GrabCut – Interactive Foreground Extraction 11