Seam Carving: problem: target many devices How to Rescale scaling? - - PDF document
Changing Image Size while keeping content intact Seam Carving: problem: target many devices How to Rescale scaling? cropping? seam carving! P Pictures CS 176 Winter 2011 CS 176 Winter 2011 1 2 Basic Idea Seams in Action
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problem: target many devices scaling? cropping? seam carving!
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one pixel from each (and every)
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monotonic, continuous cost is evaluated per pixel
e g centered difference
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e.g., centered difference other cost measures…
find by dynamic programming
optimal substructure… lots over overlapping sub problems
from second to last row
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insert seams as interpolants of
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insert seams as interpolants of
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what order for given size? dynamic programming again
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binary array of decisions
lower or higher energy on demand
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lower or higher energy on demand
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energy after removing seam?
could go up!
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(c) ariel shamir
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Energy Reduced Energy Increased
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pi-1,j-1 pi-1,j pi-1,j+1 pi-1,j-1
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pi,j-1 pi,j pi,j+1 pi,j pi-1,j-1 pi-1,j pi-1,j+1 pi-1,j-1
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pi,j-1 pi,j pi,j+1 pi,j
pi-1,j+1 pi-1,j pi-1,j-1 pi-1,j+1
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pi,j+1 pi,j pi,j-1 pi,j pi-1,j pi-1,j-1 pi-1,j+1 pi-1,j
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pi,j-1 pi,j pi,j+1 pi,j
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set up graph so that optimal seam
or LP
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or LP
expensive…
need other tricks to make practical
we’ll ignore that for now
Kwatra et al. Siggraph 2003, Graph cut textures
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connected monotonic
Connected Piecewise
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pi j pi j+1
x
pi,j pi,j+1
x CS 176 Winter 2011
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pi+1,j pi,j pi+1,j+1 pi,j+1
y x y
pi+1,j pi+1,j+1
y y x
S T
pi,j pi,j+1
x CS 176 Winter 2011
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pi+1,j pi+1,j+1
y y x
S T
monotonic connected
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monotonic connected
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