fast 3d scanning with portable mobile mapping systems

2017 annual meeting Centre for Digital Heritage

Heritage under Threat:

FAST 3D SCANNING WITH PORTABLE MOBILE MAPPING SYSTEMS Erica Nocerino FBK - Fondazione Bruno Kessler 3DOM – 3D optical metrology unit Trento, Italy web: http://3dom.fbk.eu email: [email protected]

Faculty of Archaeology, Leiden University

Speech outline 

MOTIVATIONS



DESCRIPTION OF THE INVESTIGATED SYSTEMS



PERFORMANCE EVALUATION



CASE STUDY



CONCLUDING REMARKS

Heritage under threat: fast 3D scanning with portable mobile mapping systems

2

Motivations Heritage is endangered, owing to natural causes, political and religious conflicts, looting and vandalism, man driven climate changes.

Bamyan (Afghanistan) Buddhas destruction, 2001

L’Aquila (Italy) earthquake, 2009 Heritage under threat: fast 3D scanning with portable mobile mapping systems

Emilia Romagna (Italy) earthquake, 2012 3

Motivations Engineers, surveyors and researchers in geomatics have to provide efficient methods and viable solutions for documenting, studying, preserving and valorising heritage.

PHOTOGRAMMETRY

CLASSIC SURVEYING

LASER SCANNING Heritage under threat: fast 3D scanning with portable mobile mapping systems

4

Motivations MOBILE MAPPING SYSTEM - MMS ‘compound’ system consisting of: •

mapping sensors for 3D/2D data (point coordinates and/or images)

•

positioning and navigation unit spatial referencing (Global Navigation Satellite System +Inertial Measurement Unit)

•

central system for data synchronization and integration.

Laser scanner

GNSS

Camera IMU

http://www.geocenter.fi/riegl/rieglvmx-450/


5

Motivations

Portable MMSs – some examples

http://www.gexcel.it/it/soluzioni/heron

http://viametris.info/iMS3D/EN/

https://www.applanix.com/products/timms-indoor-mapping.htm

http://www.vexcel-imaging.com/products/ultracam-panther/


6

Motivations A lightweight and portable mobile mapping system is attractive for surveying difficult to access places in a short time


7

Motivations

85m



BUT, will it work correctly always and in all conditions??

Our aim is to adopt a critical approach for assessing and exploiting the metric potentialities of systems


8



MOTIVATIONS



DESCRIPTION OF THE INVESTIGATED SYSTEMS 1)

GeoSlam ZEB1

2)

GeoSlam ZEB-REVO

3)

Leica PEGASUS: BACKPACK






CASE STUDY



CONCLUDING REMARKS

1)

2)

3)


9

The ZEB scanner systems  

By GeoSLAM (http://geoslam.com/) Hand-held laser scanner coupled with IMU sensor (NO GPS!)



Backpack containing data-logger and battery



SLAM (simultaneous localization and mapping) based process for data registration (initialization, deinitialization and loop-closure required)



Automatic processing: intervention/refinement possible!

no


2D laser IMU

manual 10

The ZEB scanner systems 

1st version: ZEB1  equipped with a spring to allow both ‘front-back’ (fb) and ‘side-by-side’ (sbs) nodding of the scan head (fb) (sbs)


11

The ZEB scanner systems 

2nd version: ZEB-REVO  auto-rotating scan head


12

The PEGASUS: BACKPACK GNSS 2D laser



By Leica (http://leica-geosystems.com/)



Backpack with 2 laser profilometers, 5 cameras, GNSS and IMU

Cameras



SLAM based process for data registration in GNSS denied environment



Possibility of improving the alignment results through manual intervention (GCPs and 3D tie points)


13

The investigated MMS

ZEB1 30 m 15-20 m 1 ToF

ZEB-REVO 30 m 15-20 m 1 ToF

Scanner data acquisition rate

43,200 points/sec

43,200 points/sec

horizontal Scanner Resolution vertical Scanner angular FOV Channels Laser wavelength Scanner line speed Laser head rotation speed Scanner weight Scanner dimensions

0.25° 3.5° 270° x 150° 1 905 nm 40 Hz 1.0 kg 60 x 60 x 360 mm

0.625° 1.8° 270° x 360° 1 905 nm 100 Hz 0.5 Hz 1.0 kg 86 x 113 x 287 mm

indoor outdoor # Laser scanners Measuring principle

Max range


Pegasus:Backpack 50 m

2 ToF 300,000 points/sec per scanner

0.1°-0.4° 2.0° 360° x 30° per scanner 16 per scanner 903 nm 5-20 Hz 0.83 kg per scanner 72 x 72 x 72 mm per scanner

14

The investigated MMS

# Cameras CCD / pixel size Focal length Cameras total angular FOV Cameras max frame rate IMU type GNSS Relative accuracy Absolute position accuracy

indoor

outdoor Tot system weight Backpack dimensions

ZEB1 0

Pegasus:Backpack 5 2046 x 2046 / 5.5 um x 5.5 um per camera 6.0 mm 360° x 200° 8 Hz MEMS MEMS FOG Triple band, single and dual antenna support 2-3 cm 2-3 cm 3-5 cm 5-50 cm (10 mins scanning, minimum 3-40 cm 3-30 cm (5 mins scanning, 1 (10 mins scanning, 1 3 loop closures or double passes conditions) loop) loop) 5 cm 3.6 kg 4.1 kg 11.9 kg 220 mm x 180 mm x 220 mm x 180 mm x 310 mm x 270 mm x 730 mm 470 mm 470 mm


ZEB-REVO 0

15



MOTIVATIONS






PERFORMANCE EVALUATION 

Performance indoor: - 50m corridor - 2 floors tests



Performance outdoor: Trento cathedral square

CASE STUDY



CONCLUDING REMARKS


https://www.cultura.trentino.it/eng/Festivals-andseasons/The-museum-and-the-town.-Thematicitineraries-exploring-Trento



16

ZEB1 – 50m corridor test PLANE FITTING: 

Smooth and homogeneous surface



Horizontal and vertical



Single and two scan passes

ZEB1: RMS  1cm Heritage under threat: fast 3D scanning with portable mobile mapping systems

17

ZEB1 – 50m corridor test



ROUND TRIP vs ONE WAY



FRONT-BACK vs SIDE-BY-SIDE nodding



REF LENGTH BY LEICA DISTO A6 (measuring accuracy = ±1.5mm)


18

ZEB1 – 50m corridor test Reference distance 52.77 m

CORRIDOR LENGTH

% RELATIVE ERROR - LENGTH

Z VARIATION

Front-Back / Round Trip

52.51 m

-0.49 %

< 0.02 m

Front-Back / One Way

52.79 m

0.04%

 0.60 m

Side-By-Side / Round Trip

52.74 m

-0.06 %

< 0.02 m

Side-By-Side / One Way

52.78 m

0.02 %

 0.60 m

ACQUISITION PROTOCOL


19

ZEB-REVO & PEGASUS – 2 floors test 

2 FLOORS



1 LOOP, 15 mins scanning



REF MEASUREMENTS BY LEICA HDS7000 (ToF phase-shift laser scanner)

&


VS

20

ZEB-REVO & PEGASUS – 2 floors test HDS7000 ZEB-REVO PEGASUS


21

ZEB-REVO & PEGASUS – 2 floors test HDS7000 ZEB-REVO PEGASUS

Noise estimation: RMS of fitting procedures Vertical planes Horizontal planes Cylindrical columns

HDS7000 0.1 cm 0.2 cm 0.1 cm


ZEB-REVO 1.1 cm 0.9 cm 0.9 cm

Pegasus 1.9 cm 1.2 cm 1.8 cm 22

ZEB-REVO & PEGASUS – 2 floors test Length measurement error


23

ZEB-REVO & PEGASUS – indoor evaluation HDS7000

ZEB-REVO

Pegasus

Dr [m]

σ[cm]

Dm [m]

σ cm]

RLME(1)

RLMA(2)

Dm [m]

σ[cm]

RLME(1)

RLMA(2)

L

45.112

0.4

45.135

0.7

0.051%

1:2000

45.133

0.9

0.047%

1:2000

B1

14.888

0.5

14.906

0.6

0.115%

1:900

15.227

8.3

2.274%

1:50

B2

14.836

0.3

14.851

2.0

0.103%

1:1000

14.925

0.8

0.600%

1:150

H1

3.021

0.2

3.021

0.3

-0.001%

1:7000

3.094

7.3

2.416%

1:50

H2

7.666

0.5

7.659

0.6

-0.087%

1:1000

7.814

1.7

1.941%

1:50

(1) Relative length measurement error:


(2) Relative length measurement accuracy:

24

ZEB-REVO & PEGASUS – indoor evaluation HDS7000

ZEB-REVO

Pegasus

Dr [m]

σ[cm]

Dm [m]

σ cm]

RLME(1)

RLMA(2)

Dm [m]

σ[cm]

RLME(1)

RLMA(2)

L

45.112

0.4

45.135

0.7

0.051%

1:2000

45.133

0.9

0.047%

1:2000

B1

14.888

0.5

14.906

0.6

0.115%

1:900

15.227

8.3

2.274%

1:50

B2

14.836

0.3

14.851

2.0

0.103%

1:1000

14.925

0.8

0.600%

1:150

H1

3.021

0.2

3.021

0.3

-0.001%

1:7000

3.094

7.3

2.416%

1:50

H2

7.666

0.5

7.659

0.6

-0.087%

1:1000

7.814

1.7

1.941%

1:50

(1) Relative length measurement error:


(2) Relative length measurement accuracy:

25

Outdoor evaluation

https://www.cultura.trentino.it/eng/Festivals-and-seasons/Themuseum-and-the-town.-Thematic-itineraries-exploring-Trento

CATHEDRAL SQUARE IN TRENTO (ca. 80x70m)

MOVING OBJECTS (people, cars, buses, etc.) &

HIGH MOUNTAINS ALL AROUND


26

Outdoor evaluation Laser scanner

GNSS

Camera IMU

COMPARISON WITH RIEGL VMX-450 MMS

http://www.geocenter.fi/riegl/rieglvmx-450/

Manufacturer SPECS Accuracy

8 mm, 1σ

Precision

5 mm, 1σ

Absolute position

20-50 mm

Data acquisition rate

1.1 million points/sec


27

Outdoor evaluation https://www.cultura.trentino.it/eng/Festivals-and-seasons/Themuseum-and-the-town.-Thematic-itineraries-exploring-Trento

28 Heritage under threat: fast 3D scanning with portable mobile mapping systems

ZEB1 ZEB-REVO

Pegasus

ZEB1 – outdoor evaluation 

ZEB1 vs RIEGL VMX-450 MMS: GLOBAL 

Robust statistical analysis after outlier removal (non-normal error distribution) [m]


MEDIAN

-3.9 cm

MAD (median absolute deviation )

1.9 cm

Deviation 95% population

8.8 cm

29

ZEB-REVO – outdoor evaluation 

ZEB-REVO vs RIEGL VMX-450 MMS : GLOBAL 



MEDIAN

2.0 cm


1.5 cm


23.9 cm

30

PEGASUS – outdoor evaluation 

PEGASUS vs RIEGL VMX-450 MMS : GLOBAL 



MEDIAN

1.0 cm


6.5 cm


50.9 cm

31



MOTIVATIONS









CASE STUDY 



WWI fort

CONCLUDING REMARKS


32

VAST project VAST - History and territory valorization to document and valorise Austro-Hungarian fortresses on the plateaus and highlands of southern east of Trentino now in ruins (burst by fascists), difficult to visit especially in winter time (≈1500-1900 m elevation)


33

VAST project Integration of acquired 3D data and historical information (photos, design drawings) to produce 3D digital models of the original appearance of the forts

LASER SCANNING

DESIGN DRAWINGS

3D DIGITAL MODEL


34

Case study: WWI fort 

SURVEYED with ZEB1 & ZEB-REVO 

18 separate scans for the main building (60x10x10 m): 3 floors, 6 rooms



4 scans for 2 underground tunnels more than 120 m and 160 m long



Acquisition time: max 20 minutes for scan



Front-back & side-by-side “round trip” scanning approach



Merged point cloud: > 200 million points


35


INITIAL ALIGNMENT ERROR


36


POST ALIGNMENT CORRECTION:


37


ALIGNMENT ISSUES: central tunnel > 160 m long 

Failed both with ZEB1 and ZEB-REVO

10m

20m


38


ZEB POINT CLOUD COLORIZED WITH 2 GOPRO


39

Case study: WWI fort EXAMPLE OF DERIVED 2D SECTION


40

Case study: WWI fort NOW UNDER RESTORATION 

Image from UAV flight realized on June 12th


41

Concluding remarks 

Performance assessment of portable mobile mapping systems



The system has proved to meet the declared performances in standard environmental conditions



Useful for fast mapping of complex environment



Careful acquisition planning is needed



External checks are crucial to assess the quality of the results


42

Concluding remarks 

Performance assessment of portable mobile mapping systems



The system has proved to meet the declared performances in standard environmental conditions



Useful for fast mapping of complex environment



Careful acquisition planning is needed



External checks are crucial to assess the quality of the results

FUTURE ADVISABLE DEVELOPMENTS WITH ZEB SYSTEMS 

Need to include external constraints in the final registration!



Possibility to acquire intensity or RGB values


43

Acknowledgments



Fabio Menna, Isabella Toschi and Fabio Remondino, FBK3DOM, for their support in conceiving this research, in data acquisition and analysis



Elisa Farella, ‘Federico II’ University of Naples, for the processing of ZEB1 data



Pablo Rodríguez-Gonzálvez, Universidad de Salamanca, for the robust statistical analysis



Nadia Guardini, Me.s.a. srl, for providing the ZEB1 and ZEBREVO



Marco Formentini and Simone Oppici, Leica Geosystem Italy, for proving the Pegasus:Backpack


44

fast 3d scanning with portable mobile mapping systems

fast 3d scanning with portable mobile mapping systems

Suggest Documents

Mobile Mapping Systems - 3D Laser Mapping [PDF]

PORTABLE MOBILE MAPPING

Understanding portable 3D scanning technologies - Creaform

MOBILE MAPPING SYSTEMS - CiteSeerX

Mobile Mapping Systems - GORDON PETRIE

Mobile Mapping Systems - GORDON PETRIE

Portable and Mobile Systems in Assistive Technology

Mobile 3D Mapping with a Low-Cost UAV System - i3mainz

3D Mapping with Google Smartphones

Photorealistic 3D Mapping of Indoors by RGB-D Scanning Process

DEFORMATION ANALYSIS WITH 3D LASER SCANNING

A MAN-PORTABLE, IMU-FREE MOBILE MAPPING SYSTEM

Editorial : Portable Learning - Experiences with Mobile Devices

Mobile scanning system for the fast digitization of existing ... - CiteSeerX

Low cost mobile mapping systems: an Italian

smartphones based mobile mapping systems - ISPRS Archives

An Overview of Mobile Mapping Systems

land-based mobile mapping systems - Google Sites

3D Transformations - 3D Scanning, Digital Modelling

Towards Fast and Portable Microkernels - Operating Systems Group

A Fast and Portable Realizer for Text Generation Systems

Mobile laser scanning (Mls)

From 3D scanning to 3D printing

Semi-Automatic Low cost 3D Laser scanning systems ...