Modeling and Rendering Architectures from Photographs

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Modeling and Rendering Architectures from
Photographs

• Lee Ji-eun

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Motivation

• modeling in VR
• geometry-based and image-based approach in
  modeling
• Modeling and rendering architecture from
  photographs, Debevec, 1996
• modeling curved architecture from photographs
  (proposition)

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(No Transcript)
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Hybrid Approach in Modeling

• Geometry-based and image-based modeling

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Photogrammetric Modeling

• Steps in users view
• Model representation
• Model reconstruction

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Model representation

• components of a scene
• block
• reference to a named symbolic variable
• parametric polyhedral primitives by Debevec
• parametric curved primitives (proposition)
• relation
• spatial relationships between blocks
• generally constraints rotation and translation
• scene
• constrained hierarchical model of blocks and
  relations

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Debevec
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Borchoukov
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Lee Ji-eun
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Reconstruction Algorithm

• define the error estimation formula
• minimize the error with appropriate numerical
  method

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Initial Estimation
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Case Polyhedral object

• Minimize the disparity between the edge on image
  and the edge on model

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Case sphere

• parameter
• radius
• user interaction
• measure diameter
• error estimation

ro
rp
Lo
Lp
r predicted/observed radius L
predicted/observed length of a base
straight line
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Case hemi-sphere

• parameters
• radius, length of a secant line d
• user interaction
• measure diameter
• measure diameter on the secant circle
• error estimation

ro
rp
do
dp
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Case cylinder
ro

• Parameters
• radius, height
• user interaction
• mearsure diameter
• mark height
• error estimation

rp
ho
hp
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Case rotational swept object

• Definition of rotational swept object
• axis of revolution
• profile list of edges
• Two-pass reconstruction
• first pass axis
• second pass profile

eo edge on image ep projected edge of s1
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Case Block with curves

• Minimize the disparity between the curve on image
  and the curve on model
• curve representation 3-order Bezier curve

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COP aligned with world coordinate system
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Case Block with curves (cntd)

• Curve on model (3-order Bezier curve)
• Projection of Q(t) on image plane
• Curve on image
• approximation of 3-order Bezier curve from points
  on image curve

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Case Block with curves (cntd)

• Error definition
• Objective function definition
• Goal
• P2, P3 with minimum objective function value

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Future work

• Modeling
• more precise depth information
• Rendering
• View-dependent texture mapping
• (Real-time process required for Navigation)
• Nonlinear image warping for curved object