segmentation reporter: xiaoqun wu date: 2008/10/30
TRANSCRIPT
Segmentation
Reporter: Xiaoqun WuDate: 2008/10/30
Papers
Patch-type Segmentation of Voxel Shapes using Simplified Surface Skeletons
Part-type Segmentation of Articulated Voxel Shapes using the Junctions Rules
Authors Dennie Reniers
Ph.D Student of Dept. of Mathematics and Computing Science at Tu/e
His research interests include shape analysis, representation and segmentation, and discrete geometry
Alexandru Telea Assistant Prof. of Dept. of Mathematics and Computing Science at Tu/e
The Problem
Two Types
Patch-type Segmentation: Geometry-Oriented
Part-type Segmentation Semantically-Oriented
Two Types
Patch-type Part-type
Conceptions Surface skeleton
Curve skeleton
Patch-type Segmentation of Voxel Shapes using Simplified Surface Skeletons
Patch-type Segmentation Main idea:
The boundaries of the surface skeleton map one-to-one to the edges of the 3D shape
Edge DetectionCompute Surface Skeleton
Simplify Skeleton
Edge ErosionHandling Corners
Surface Skeleton
Distance Transform
Feature Transform
Surface Skeleton
: the minimum distance to the boundaryD R
: ( )
( ) { | ( )}
F P
F p q p q D p
( ) { | ( ) 2}S p F p
Surface Skeleton
Foreground Skeleton
Background Skeleton
Surface Skeleton
Background Skeleton
Simplify Skeleton
Importance Measure The length of shortest path on the surface boundary b
etween two feature points F(p)
Simplified Skeleton
, , {0,1}( ) ( , , ) is extended feature transformx y z x y zF p F p x p y p z
, ( )( ) max ( , ) g is the shortest path between a,b
a b F pp g a b
S ( ) { | ( ) }p p
Simplify Skeleton
Simplify SkeletonS ( ) { | ( ) }p p
Edge Detection
Feature collection
Convex Edges
Concave Edges
Edges
( )( ) ( )
p SV S F p
1{ | min ( , ) }
2 nv V
E q g q v
1{ | min ( , ) }
2 nv V
E q g q v
E E E
Edge erosion
Handling Corners
Complexity
Results
Results
Comparison
Part-type Segmentation of Articulated Voxel-Shapes using the Junction Rule
Main idea
Main steps
Compute Curve
SkeletonSimplify Skeleton Detect Junction
Place Part Cuts
Surface Skeleton
Distance Transform
Feature Transform
Surface Skeleton
: the minimum distance to the boundaryD R
: ( )
( ) { | ( )}
F P
F p q p q D p
( ) { | ( ) 2}S p F p
Curve Skeleton
The set of shortest paths
Curve Skeleton
, ( )( ) ( , )
a b F pp a b
( ) contains a Jordan Curve
Jordan Curve is a simple closed curve on the boundary
p C p
Curve Skeleton
Simplify Curve Skeleton
C +
i 1
C
C
: ( ) the component set
: C R the importance measure
1 C
( )
if ( ) , discard
i
k
C C P
i k C
p C
p p
Detect Junction
Place part cut
Place part cut
Geodesicness measure
The larger, the better
Place cut part
Results
Results
Results
Results
Comparison
Conclusion
Two Methods Patch-type Segmentation
Surface Skeleton
Part-type Segmentation Curve Skeleton
Thank you!