hands and face tracking for vr applications
DESCRIPTION
Hands and face tracking for VR applications. Javier Varona, Jose’ M. Buades, Francisco J. Perales Unidad de Gra´ficos y Visio´n por Ordenador, Dept. de matematiques i Informatica, Universitat de les Illes Balears (UIB), crta. Valldemossa km. 7,5, 07122 Palma de Mallorca, Spain. - PowerPoint PPT PresentationTRANSCRIPT
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Hands and face tracking for VR applications
Adviser: Chih-Hung Lin
Date:2010/12/14
Speaker: Chin He Hsu
Javier Varona, Jose’ M. Buades, Francisco J. Perales Unidad de Gra´ficos y Visio´n por Ordenador, Dept. de matematiques i Informatica, Universitat de les Illes Balears (UIB), crta. Valldemossa km. 7,5, 07122 Palma de Mallorca, Spain
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Outline1.Introduction
2. Hands and face tracking algorithm
3.Visualization using H-Anim
4.Conclusion and future work
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• system must detect a new user– entering into the system’s environment– analyse him to set parameters– tracking interesting regions
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2. Hands and face tracking algorithm
• tracking problem lies in identifying both hands and face in each image – detect skin-colour pixels– data association algorithm
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2.1. Skin-colour segmentation module
• skin-colour detection– necessary to model the actor’s skin-colour in a pre
vious step
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skin-colour sample
• transform these pixels from the RGB-space to HSL-space– hue and saturation values contain the chroma infor
mation
• two main problems– human skin hue values are near the red colour– saturation values are near 0
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skin-colour distribution
•
• Gaussian model
•
•
1{ ,..., ,..., }, ( , )i n i i iX x x x x h s
1
1 n
ii
x xn
1
1( ), ( ) '
n
i ii
x x x xn
1
2
1 1( is skin) exp( ( )| |( )' )
2(2 ) | |p x x x x x
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2.2. Data association module
•
s (p , w , )l l l l
p ( , ):position in the 2D image
w ( , ) : size of the limb in pixels
: angle in the 2D image plane
x yp p
w h
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Next linear scheme of prediction
•
• that an extreme limb will maintain the same velocity
p( ) p( ) p( 1)
p( ) p( ) p( 1)
t t t
t t t
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Set of hypothesis
•
•
{h }, 3,
Where
h (p , w , )
l
l l ll
H l
1{ ,..., ,..., }, : blob with labeli M iB b b b b
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• define an approximation to the distance from the x image pixel to the hypothesis h
• t=x p
n=R t',
where
cos sinR=
sin cos
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calculating the angle
• Normalized image pixel and the hypothesis centre
•
atan( / )x yn n
c ( , ),crossing point
cos
sin
x y
x
y
c c
c w
c h
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• distance between an image pixel and a hypothesis
•
• if d( x ,h)<=0 , then x is inside the hypothesis h ,if d( x
,h)>0 , then x is outside the hypothesis h
(x,h) || n || || c ||d
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• a blob with empty intersection with all hypotheses
• a pixel x of a blob is inside a limb hypothesis
x , min{ (x,h)} 0h H
b d
x , x= iff { (x,h)} 0B l d
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3. Visualization using H-Anim
• H-Anim (humanoid animation)
• we use the H-Anim standard, this way we can collaborate with standard VRML (Virtual Reality Modeling Language ) models