Download presentation

Presentation is loading. Please wait.

Published byDevin Harper Modified over 4 years ago

1
My PhD Thesis Work l With: n Tony DeRose (Computer Science) n Tom Duchamp (Mathematics) n John McDonald (Statistics) n Werner Stuetzle (Statistics) n... (University of Washington, 91-94)

2
3D Scanning digital model physical object computer-aided design (CAD) reverse engineering/ 3D scanning shapecolormaterial surface reconstruction

3
Why 3D scanning? l Digital models for many objects dont exist. n reverse engineering (Boeing 737X) n archiving n virtual environments l Traditional design (using clay) n car industry n computer animation l 3D faxing!

4
Surface reconstruction points P surfaceS l reverse engineering l traditional design (wood,clay) l virtual environments

5
smooth surfaces B-spline Previous work subdivision implicit meshes simple surface topological type [Schumaker93], … arbitrary [Sclaroff-Pentland91],... - [Schmitt-etal86],[Forsey-Bartels95],..., [Hoppe-etal92,93], [Turk-Levoy94],... [Moore-Warren91],[Bajaj-etal95] [Hoppe-etal94] [Krishnamurthy-Levoy] … [Krishnamurthy-Levoy] [Eck-Hoppe96],…

6
Surface reconstruction problem l Given: points P sampled from unknown surface U l Goal: reconstruct a surface S approximating U n accurate (w.r.t. P, and U!) n concise n concise

7
Why is this difficult? l Points P n unorganized n noisy l Surface S n arbitrary, unknown topological type n sharp features l Algorithm must infer: n topology, geometry, and sharp features

8
3-Phase reconstruction method phase 1 points initial mesh optimized mesh optimized subdivision surface phase 2 phase 3 Find piecewise smooth surface. Find initial surface of correct topological type. Detect sharp features automatically Improve its accuracy and conciseness. Goals: [SIGGRAPH92] [SIGGRAPH93] [SIGGRAPH94]

9
Example 12 3 13,000 points

10
Phase 1: Initial surface estimation l If U were known, it would satisfy U = Z(d) = { p | d(p)=0 }, where d(p) is the signed distance of p to U U d(p)? + + + + + + + + + + + + ++ + + + + + + + + + + + – – – – – – – – – – – d(p)?

11
Estimate d from P Extract Z(d) S P

12
Phase 1 (contd) l How to estimate d? compute tangent planes orient them consistently

13
Phase 1 (contd) l How to extract Z(d)? run marching cubes

14
Phase 2: Mesh optimization l Input: data points P, initial mesh M initial l Output: optimized mesh M, minimizing E(M) = E distance + E complexity 2

15
Phase 2 (contd) l Optimization over: n the number of vertices n their connectivity n their positions consider any mesh of the same topological type as M initial

16
Phase 2 (contd) Nested optimization: l optimize connectivity l for fixed connectivity, optimize geometry edge collapse edge swap edge split Greedy approach: n consider local perturbations accept if E(M)<0 accept if E(M)<0

17
Phase 2: Results using 31,000 points from Digibotics, Inc. using 13,000 points using 182,000 points from Technical Arts Co.

18
Phase 3: Piecewise smooth surface piecewise piecewise surface piecewise planar piecewise smooth surface 3

19
Subdivision surfaces M0M0M0M0 M1M1M1M1 M2M2M2M2 S=M S=M [Loop87] tagged control mesh [Hoppe-etal94]

20
Phase 3 (contd) l Generalize phase 2 optimization: edge collapse edge swap edge split edge tag Again, apply perturbation if E(M)<0 Again, apply perturbation if E(M)<0

21
Phase 3: Results

22
Related work phase 1 initial mesh optimized mesh optimized subdivision surface phase 2 phase 3 volumetric repr. (Curless&Levoy) alpha shapes (Edelsbrunner) CAD models (Sequin) NURBS surface (Krishnamurthy&Levoy) (Eck&Hoppe)

Similar presentations

OK

Tracking Surfaces with Evolving Topology Morten Bojsen-Hansen IST Austria Hao Li Columbia University Chris Wojtan IST Austria.

Tracking Surfaces with Evolving Topology Morten Bojsen-Hansen IST Austria Hao Li Columbia University Chris Wojtan IST Austria.

© 2018 SlidePlayer.com Inc.

All rights reserved.

To make this website work, we log user data and share it with processors. To use this website, you must agree to our Privacy Policy, including cookie policy.

Ads by Google

Ppt on congruent triangles for class 7 Ppt on review of literature format Ppt on electrical engineering major projects Free ppt on water cycle Ppt on hepatitis b virus Ppt on electricity distribution system in india Ppt on telephone etiquettes Ppt on acid-base indicators tea Ppt on advertising media planning Ppt on obesity prevention program