3D Scanning for museums

Kirk Martinez

University of Southampton

Overview

Why?

Techniques availableLaserimage-based

Summary

Motivation

2d representations don’t capture 3D objects well

Any 2-D view can be generated from a single 3-D model.

3D studies can be donemodels can be compared/searched

Examples of scanners

Cyberware Digibotics 3dscanners

MensiPolhemus

Structured light scanning

• example from CNR Italy

Michelangelo project

• by Stanford

• used Cyberware

Arius 3D

• laser based – developed by CNR Canada

• RGB lasers give colour

Issues

•Some objects can be very large e.g. building

•Objects can be very complex e.g. lots of holes

•Lighting conditions often very important

•File formats and browsers

•Cost

Image-based 3D reconstruction techniques

• Image sequences of rotating objects• Two approaches used:

– Silhouette-based only approach: CANON software– Silhouette and multi-stereo technique: GET-ENST

approach• For less complex objects with textured surface • Required:

– good quality image sequences (precise turntable, good lighting, photographic know-how)

– good silhouette segmentation

Turntable approach

• ENST scanner

3D laser acquisition & reconstruction

• Using MINOLTA Vi 900 laser scanner (ARCHIDATA)

• Using reconstruction software– Rapidform® (C2RMF, Cherbourg) – Maya® (Quai Branly)

• User partners involved– White clay Gallo-Roman figurines and moulds:

• C2RMF - Bourbon-Lancy

• C2RMF - Moulins

– Miscellaneous• C2RMF - Cluny

• Cherbourg

• Quai Branly (external partner, negotiation for collaboration in progress)

Outdoor scanning example

• Coloseum in Rome with Minolta laser scanner

3D Laser: Cherbourg

Cherbourg_laser 17 Cherbourg_laser 13 Cherbourg_laser 12

Cherbourg_laser 03 Cherbourg_laser 18 Cherbourg_laser 14

Image-based 3D reconstruction: VAM

33 objects: statuettes, ceramic French vases

GET-ENST silhouette and multi-stereo technique

3D

Image-based 3D

Image acquisition

Camera calibration

3DReconstruction

Texture mapcreation

57639 sommets, 115282 triangles

Results

385355 sommets770209 triangles

233262 sommets466520 triangles

Scanner laser 3D MinoltaMethode proposée

Results compared with laser

bigHead buddha dragon

masque twins

african3

Image-based 3D reconstruction: GET-ENST Examples

Summary

•Cost / quality / time trade-offs

•Techniques vary in:•mesh quality•texturing quality

•some scanners are better suited to some materials•smaller 3D models are simple to put on Web