Continuous Medial Representations for Geometric Object...
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Continuous Medial Representations for Geometric Object Modeling Wei Liu Mar 18, 2010
Transcript of Continuous Medial Representations for Geometric Object...
Continuous Medial Representations for Geometric Object Modeling
Wei LiuMar 18, 2010
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Methods to define skeleton of object
● maximal inscribed ball
● Hierarchal Voronoi
● Shock of boundary evolution
● core tracking.
● mrep
● cmrep
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Mrep: Inverse skeletonization
● Traditional: the intersection of the normal.
● Now: a medial point with two boundary point.
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Mrep: sampling
● Medial point are sampled on the axis.
● A sparse representation.
● Sampled medial points are fixed relative to the axis.
http://midag.cs.unc.edu/defmreps/jl3_movie2.gif
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Continuous mrep: cmrep
● Can move the medial points along the axis.
● Generate a synthetic given set of bspline control points.
● Maximize overlapping between this shape and template by adjusting control point.
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●When ||del r|| = 0, meaning r does not change, U = N.
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Bspline interpolation
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constraints
● Closed● Connected● nonsingular
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Parameter estimation
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Parameter estimation
● Obj F = prior + Energy ● Prior: prefer low curvature.
Energy: mean square distance between interpolated boundary and target shape, summed over all sampled points.
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Narrated Quicktime movie about model construction in 3D (.mov with audio, 3 min, 11mb)
Narrated Quicktime movie about fitting models to images in 3D (.mov with audio, 90 sec, 18mb)
Movie of a spinning 3D model of the hippocampus (.avi loop, 200kb)
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