institute of computing technologychinese academy of sciences 1 a pose-independent method of...

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INSTITU

TE OF CO

MPU

TING TECH

NO

LOGY

CHIN

ESE ACADEMY O

F SCIENCES

A Pose-Independent Method of Animating Scanned Human Bodies

Yong Yu, Tianlu Mao, Shihong Xia, Zhaoqi Wang

Institute of Computing Technology, Chinese Academy of Sciences

http://vr.ict.ac.cn/index_en.htm

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INSTITUTE OF COMPUTING TECHNOLOGY

Outlines

Goal Previous Methods Our Method

Segmentation Skeleton Extraction Skin Deformation

Results Conclusion & Future Work

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Goal

To animate scanned human bodies

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Previous Methods

Model Mapping [Seo03] To map a skeleton and skin deformation of a tem

plate model to a scanned human body Pose-independent, require a template model

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Previous Methods

Model Intersecting [Ju00, João03] To intersect scanned body into contours with horizontal planes. To extract joints according to perimeters or average radiuses of t

he contours. Automatic, pose-dependent

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Previous Methods

Model Segmentation [Xiao03, Werghi06] To utilize Morse theory to segment scanned huma

n body Pose-independent, only segmentation

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Previous Methods

Puppet Rigging [Baran07] To rig and animate 3D puppets Pose-independent, orientation-dependent

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Key Issues

Pose-independent How to animate scanned human body in different

poses or in different orientations?

Automatic Does the method perform automatically?

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Animating scanned body

Segmentation

Skeleton Extraction

Skin Deformation

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Geodesic distance from x to a source point

Morse Functions

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( ) ( , )n

ii

m x g x v

( ) ( , )sourcem x g x v

( ) ( )m x h x

Height function [Ju 00]

Sum of geodesic distances from x to all points [Werghi 06]

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Segmentation

Source Point Candidate Considering symmetry

Bilateral symmetry Front and back symmetry Both symmetry

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Segmentation - source point

Source point:

Top of head

Source point:

Crotch

vs

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Segmentation

Source Point and Feature Points

a b c

e f g

Source Point

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Segmentation

( ) ( , )headm x g x v

Morse function isolines,Contours

Topological structure Segments

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Skeleton Extraction

Assumption： Contours at joints are irregular ; the other contours are m

ore regular and more similar to a circle Circularity Function

(to estimate similarity degree between a contour and a circle)

Joint Extraction

Mjoint is a joint contour Circularity function gains local minimum in joint contour w

hose center is a true joint

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4 ( )( )

( )i

ii

s Mh M

c M

2

4 ( )arg min( ( )) arg min( )

( )i

joint ii

s MM h M

c M

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Skeleton Extraction

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Skin Deformation

Skeleton Subspace Deformation

Separating Contours Joint Contours – for all joints except shoulders an

d thighs Additional Contours – for shoulders and thighs

1,

1

n

c i i i d di

P w R R P

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Joint Contours

2 21

2 1 2 1

( ) ( )

( ) ( )xM M m M m x

wM M m M m M

1 1

22 1 2 1

( ) ( )

( ) ( )xM M m x m M

wM M m M m M

MJ: Joint ContourM1:Region Border

M2: Region BorderDeformation

Region

1 2 J JM M M M

Skin deformation weights

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Additional Contours

a b

c d

e

Additional ContoursSegments Errors in Segmentation

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Results - Various Human Bodies

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Results - Various Postures

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Results - Various Orientations

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Results

Time5000 Faces

10000 Faces

20000 Faces

30000 Faces

Source Point Extraction 0.5s 1.4s 5.1s 14.2s

Segmentation 0.1s 0.3s 0.9s 1.4s

Joint Extraction and Skin Deformation

0.3s 0.8s 4.4s 8.8s

Total 0.9s 2.5s 10.4s 24.4s

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Conclusion and Future Work

Conclusion Pose-independent Automatic Robust

Future Work Loop in topological structure of body

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INSTITU

TE OF CO

MPU

TING TECH

NO

LOGY

CHIN

ESE ACADEMY O

F SCIENCES

Thank you

http://vr.ict.ac.cn/index_en.htm

institute of computing technologychinese academy of sciences 1 a pose-independent method of...

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