Reconstructing Non-stationary Articulated Objects in Monocular Video using

Silhouette Information

Saad M. Khan and Mubarak ShahUniversity of Central Florida, Orlando, FL, USA.

ICPR 2008

Reporter: Hsieh, Chia-HaoDate: 2009/09/07

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Introduction

• Silhouette fusion (combine color and silhouette image)

• Blurred occupancy images

• Motion deblurring of the occupancy images

• Virtual hull reconstruction by the de-blurred images

Blurred Occupancy Images

Reconstructing Non-stationary Articulated Objects in Monocular Videousing Silhouette Information

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Outline

• Scene Occupancies

• Temporal Occupancy Points (TOP)

• Building Blurred Occupancy Images

• Motion Deblurring

• Final Reconstruction

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Scene Occupancies

temporal occupancy : the fraction of total time instancesji

determines

Scene point Pi is guaranteed to be occupied in ji

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Temporal Occupancy Points (TOP)

projection projection

views from a monocular camera sequence (flyby)

Move left arm

Temporal bounding edges

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Temporal Occupancy Points (TOP)

• No complete camera calibration at each time instant no 3D information

• Purely image-based approach– Obtain the projections (images) of the TOP in

each view

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Temporal Occupancy Points (TOP)

ground plane reference systemγ

Point to point transformby homography

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Building Blurred Occupancy Images

For each silhouette image,store value τ at projected locations of TOP in each blurred occupancy images

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Motion Deblurring

Blurred occupancy image = unblurred occupancy image CONVOLUTE blur kernel PLUS noise

Blur kernel also known as the point spread function (PSF)

User specifies different crop regions of the blurred occupancy images each with uniform motion, which are then restored separately

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Final Reconstruction

• Using the method of [7]A Homographic Framework for the Fusion of Multi-view Silhouettes. IEEE ICCV 2007.

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