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Eugene Weiss Computer Vision Stanford University December 14, 2011. Automating Grab-Cut for Single-Object Foreground Images. Eugene Weiss eweiss@sbcglobal.net. 1. Automating Grab-Cut for Single-Object Foreground Images.
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Eugene Weiss Computer Vision Stanford University December 14, 2011 Automating Grab-Cut for Single-Object Foreground Images Eugene Weiss eweiss@sbcglobal.net 1
Automating Grab-Cut for Single-Object Foreground Images • Grab-Cut: Interactive Foreground Extraction Using Iterated Graph Cuts. • Invented by Rother, Kolmogorov and Blake at Microsoft Research, Cambridge in 2004. • User defines a rectangular bounding box to separate rough foreground from background. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images Automating Grab Cut • A Good bounding box doesn’t need to frame the image perfectly. • Better thought of as background subtraction than foreground identification. • So it’s better to think “outside the box”. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images First (Naïve) Pass The area in red represents the tested background slice, the rest is treated as foreground. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images Second Pass 3 sides of the naïve box are used for foreground, the slice is constrained by the perpendicular edges of the box. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images An Easy Case A clear color differentiation of the foreground from the background makes for a good result. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images A good result with a challenging image A good outcome despite a similar background color. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images Problems Images intersecting the image border present a challenge. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images Problems A portrait may want a face, or a full torso. Presently, the face is selected. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images The Hardest Image. The hardest case is where the foreground object is both complex and intersects the image edge. Eugene Weiss eweiss@sbcglobal.net
Automating Grab-Cut for Single-Object Foreground Images Future Directions • More features, such as better texture determinants. • Look at segmenting the foreground area to avoid cropping. • Use threshold to broaden the box, and hopefully solve the edge intersection prob. • Leverage Grab-Cut improvements. Eugene Weiss eweiss@sbcglobal.net