3D Modeling of Monuments: Recent Work of the IU Virtual World Heritage Laboratory

Transcription

1 3D Modeling of Monuments: Recent Work of the IU Virtual World Heritage Laboratory ` Bernard Frischer Virtual World Heritage Laboratory, Indiana University April 16, 2015

2 AGENDA Mission of the VWHL Most recent work: The Digital Atzompa Project What s next?

3 AGENDA Mission of the VWHL 3d documentation of cultural heritage artifacts, monuments, sites at various scales Increasing use of structure-from-motion approach: 2d 3d

4 In past: laser scanning Faro Arm used to scan head of a satyr in the Dresden State Museums (2007). Faro Arm used to scan Caligula in the Virginia Museum of Art (2010)

5 In past: laser scanning In last 2-3 years: photogrammetry for small artifacts Faro Arm used to scan head of a satyr in the Dresden State Museums (2007). Faro Arm used to scan Caligula in the Virginia Museum of Art (2010) Nikon D810 used to make photogrammetric model of 17C Indian throne leg. Ht: 40 cm Indianapolis Museum of Art (2015)

6 In past: laser scanning In last 2-3 years: photogrammetry for small artifacts In last year: photogrammetry for sites and landscapes Faro Arm used to scan head of a satyr in the Dresden State Museums (2007). Faro Arm used to scan Caligula in the Virginia Museum of Art (2010) GoPro Hero 4 on DJI Phantom 2 photographs the archaeological sites of Roselle (June, 2014), Cosa (June, 2014), and Atzompa, Oaxaca, Mexico (January, 2015).

7 Photogrammetry vs. laser or structured-light scanning Photogrammetry based on CS concept of structure from motion, i.e., the ability to compute the geometric shape common to a series of overlapping photographs of a scene Theory of SfM Application of theory: 146 camera shots of the Lansdowne Hercules, cast in The Dresden State Museums.

8 Photogrammetry vs. laser or structured-light scanning Photogrammetry based on CS concept of structure from motion, i.e., the ability to compute the geometric shape common to a series of overlapping photographs of a scene Theory of SfM Application of theory: 146 camera shots of the Lansdowne Hercules, cast in The Dresden State Museums.

9 Photogrammetry vs. laser or structured-light scanning Photogrammetry based on CS concept of structure from motion, i.e., the ability Advantages of photogrammetry: Inexpensive (uses digital camera, not dedicated scanner) Fast data capture (typically 30 minutes to capture life-size statue vs hours with scanner) Fast postprocessing (typically 2-3 hours for a life-size statue vs. 2-3 days with a scan model) Photogrammetry software costs far less than scan processing software such as Polyworks, Geomagic, and Rapidform Nikon D810, ca. USD $5,000 Faro Arm, ca. USD $80,000

10 Photogrammetry vs. laser or structured-light scanning Photogrammetry based on CS concept of structure from motion, i.e., the ability Advantages of photogrammetry: Inexpensive (uses digital camera, not dedicated scanner) Fast data capture (typically 30 minutes to capture life-size statue vs hours with scanner) Fast postprocessing (typically 2-3 hours for a life-size statue vs. 2-3 days with a scan model) Photogrammetry software costs far less than scan processing software such as Polyworks, Geomagic, and Rapidform Question: but is photogrammetry as accurate as scanning?

11 AGENDA Mission of the VWHL 3d documentation of cultural heritage artifacts, monuments, sites at various scales Analysis and interpretation: digital restoration example: Digital Hadrian s Villa Project ( )

12 Video available at:

13 AGENDA Mission of the VWHL 3d documentation of cultural heritage artifacts, monuments, sites at various scales Analysis and interpretation: digital restoration empirical experimentation through interactive simulations ( simpiricism ) example: Ara Pacis and Meridian of Augustus Project ( )

14 Results of virtual fieldwork: Simulation revealed that the obelisk could easily be seen by someone standing on the Via Flaminia on axis with the Ara Pacis: never noted before in the scholarship Accords with the commonplace that the main façade of the Ara Pacis was the eastern façade all the more likely if the west side overlooked a mere field, not a monumental pavement inscribed with a sundial Ara Pacis ( Altar of Peace, foreground) and Montecitorio Obelisk as seen from the east on the Via Flaminia. The altar was built from 13-9 BC; the obelisk was brought to Rome and erected in 10/9 BC.

15 Results of virtual fieldwork: testing Buchner s theory The computer simulation was used to test whether the shadow of the obelisk moves to or toward the middle of the Ara Pacis on September 23. Result: it does not. Shadow of the obelisk hits Ara Pacis off axis on September 23

16 Results of virtual fieldwork: 1 (testing Buchner s theory) In any case, what Buchner imagines happened on September 23 (but didn t) actually happened on 48 other days of the year (i.e., 24 pairs of dates: dates always come in pairs!). This is too frequent to be significant: we need some environmental effect that is rare and hence salient when it occurs

17 Results of virtual fieldwork: Simulation revealed that the obelisk could easily be seen by someone standing on the Via Flaminia on axis with the Ara Pacis: never noted before in the scholarship We wondered if from here you could ever see the sun tangent to top of obelisk

18 16:43 CET, October 9, 9 BC. Festival day of the Roman sun god, Apollo Palatinus, cult initiated by Augustus,October 9, 28 BC.

19 AGENDA Mission of the VWHL 3d documentation of cultural heritage artifacts, monuments, sites at various scales Analysis and interpretation: digital restoration empirical experimentation ( simpiricism ) ` Dissemination: online scientific reports education public outreach Khan Academy Heavy use of Sketchfab, a web service supporting publication of 3d interactive models embedable on our websites

20 AGENDA Mission of the VWHL The Atzompa Project: a partnership of INAH and the VWHL For VWHL: example of lab s mission to document cultural heritage challenge: pushes us to create largest scale 3d map we have yet made (ca. 500 x 500 m.) For INAH: documentation spatial analysis public outreach

21 AGENDA Mission of the VWHL The Digital Atzompa Project: a partnership of INAH and the VWHL Stages of the project: #1: data collection on site and in lab; >50,000 photographs from the ground and air (January 5-8, 2015) #2: Postprocessing of data (> 750 hours) #3: Feedback from INAH (March 18-21, 2015) #4: Dissemination INAH: on March 20, 2015 we delivered copy of all raw and processed data; embed codes for interactive use of 3d models on Internet VWHL: processed data added to the portfolio of our lab website

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23 AGENDA Mission of the VWHL The Atzompa Project: a partnership of INAH and the VWHL Website: access is now password-protected The archaeological site is presented through a series of 3d photogrammetric models nested in the manner of Chinese boxes from large (model of entire site) to small (individual buildings)

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25 AGENDA Mission of the VWHL The Atzompa Project: a partnership of INAH and the VWHL Website: access is now password-protected The archaeological site is presented through a series of 3d models nested in the manner of Chinese boxes from large (model of entire site) to small (individual buildings) After the overall site model follows the more detailed models of the four terraces, and for each terrace there are still more detailed models of each built element on the terrace

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27 AGENDA Mission of the VWHL The Atzompa Project: a partnership of INAH and the VWHL Website: access is now password-protected The archaeological site is presented through a series of 3d models nested in the After the overall site model follows the more detailed models of the four terraces, We give links to scientific (including popular scientific) online publications about the It is possible to go into first person mode (as in a videogame) and move forward, backward, etc. through the virtual spaces. Here we see an example of a tour of the House of the Altars.

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29 AGENDA Mission of the VWHL The Atzompa Project: a partnership of INAH and the VWHL Website: access is now password-protected The archaeological site is presented through a series of 3d models nested in the It is possible to go into first person mode (as in a videogame) and move forward, \ The website also offers 3d models of important artifacts and works of art Metadata about the artifact Paradata about the modeling process

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31 AGENDA Mission of the VWHL The Atzompa Project What s next? 3d modeling of sculpture in the Indianapolis Museum of Art

32 Magbo Society Mask. Yoruba (ca ). Ht.: 73 cm. Power Figure. Songye People (ca. 1900). Ht: 81.7 cm. Vishnu. Bengal or E. Indian (AD ). Ht: 81.3 cm.

33 AGENDA Mission of the VWHL The Atzompa Project What s next? 3d modeling of sculpture in the Indianapolis Museum of Art Studies about relative accuracy of laser scanning vs. photogrammetry

34 AGENDA Mission of the VWHL The Atzompa Project ` What s next? Conclusions The 2d to 3d revolution has arrived Lansdowne Hercules. Cast, Dresden State Museums. Ht: cm.

35 AGENDA Mission of the VWHL The Atzompa Project ` What s next? Conclusions The 2d to 3d revolution has arrived State models are important as first step on the way to restoration models Roccabruna, Hadrian s Villa: current state (left); restoration model (right)

36 AGENDA Mission of the VWHL The Atzompa Project ` What s next? Simulation of October 9, 9 BC as seen from the Via Flaminia Rome, on axis with the Ara Pacis and Montecitorio Obelisk. Conclusions The 2d to 3d revolution has arrived State models are important but generally only the first step on the way to restoration models Restoration models are important as a second step on the way to the end goal of Virtual Heritage: simpirical study of the past through simulations

37 Bernard Frischer Dept. of Informatics Indiana University bfrische AT Indiana.edu Cell: