Recording Ireland’s early Christian monuments using aerial and terrestrial laser scanning

Anthony Corns, Gary Devlin & Robert Shaw The Discovery Programme

• The Icons List for Ireland

• The Early Christian Sites

• Equipment

• Clonmacnoise

• Glendalough

• Skellig Michael

• Conclusions

Today’s Presentation

The ‘3D-ICONS’ of Ireland

Brú na Bóinne

Knowth

Newgrange

Clonmacnoise

Derry city walls

Dún Ailinne

Drombeg stone circle

Gallarus oratory

Glendalough

Hill of Tara

Loughcrew Cairn T

Navan Fort

Poulnabrone portal tomb

Rathcroghan

Skellig Michael

Stone Forts

An Grianan Ailigh

Cahergal

Dúcathair

Dún Aonghasa

Dún Eochla

Staigue

Clonmacnoise

Glendalough

Skellig Michael

The early Christian Sites

CAPTURE

• Monuments

• Artefacts

• Scanning

• Photography

• Aerial survey

MODEL

• Solids

• 3d pdf

• GML

DEPOSIT

• Repository

• Metadata

USE

• Europeana

• Education

• Tourism

• Conservation

Project pipeline

Equipment: Faro Focus 120

• Phase based laser scanner

• Distance accuracy up to ±2mm

• Range from 0.6m up to 120m

• Measurement rate up to 976,000 points/sec

• Small and compact: weighing just 5 kg

• Intensity & RGB

• Intuitive touchscreen display

• Integrated colour camera

• Photorealistic 3D colour scans with up to 70 megapixels

• Parallax-free colour overlay

Processing Path: Faro Focus

EXPORT FOR MODELLING

BENTLEY POINTOOLS SEGMENTATION CLEANING

FARO SCENE REGISTRATION GEO-REFERENCING

FARO FIELD DATA GATHERING

Equipment: Trimble VRSNOW

• Georeferencing to Irish National Grid

• Trimble 5800 dual frequency receiver

• Real Time Kinematic (RTK)

Horizontal ±10 mm + 1 ppm RMS

Vertical ±20 mm + 1 ppm RMS

• Trimble VRS Now: a subscription service

that provides instant access

to RTK corrections

Equipment: Artec EVA

• Hand held projected light scanner

• Light source: flash bulb (no laser)

• Up to 16 frames per second

• Data acquisition: up to 2 000 000 points/s

• 3D resolution, up to 0.5mm

• 3D point accuracy, up to 0.1mm

• 3D accuracy over 100cm, up to 0.03%

• Texture resolution 1.3mp

•Output formats OBJ, PTX, STL, WRML, ASCII, AOP,

CSV, PLY, E57

Processing Path: Artec EVA

EXPORT FOR MODELLING

Geomagic STUDIO 2012 (64 bit) CLEANING DECIMATION

Artec STUDIO 9 REGISTRATION APPLY TEXTURE

Artec STUDIO 9 FIELD DATA GATHERING

Clonmacnoise: Monastery

Clonmacnoise: TLS

PHASE 1 Cathedral & core buildings

• 35 separate scans

• Intensity and RGB

• VRS Now geo-referencing

• 2 days (April 15th – 16th 2013)

PHASE 2 complete monastic complex

37 separate scans

• Intensity & RGB

•Intensity and RGB

• VRS Now geo-referencing

• 2 days (July 9th – 10th 2013)

Over 1 billion points!

Clonmacnoise: Pointcloud

Clonmacnoise: Pointcloud

Clonmacnoise: Carved stones

Carved Slabs

6 proposed

6 completed 2013

High Crosses

3 proposed

Survey planned winter 2013/14

Clonmacnoise: Carved stones

Original

Deliverables:

Web GL

Surface

Wrap

3D scanning

Glendalough: Monastic City

• Project broken into

discrete sites in valley

• 12 individual

monuments to scan

• Faro Focus 120

• Completed in 8 days

Glendalough: planning

Glendalough: Point Cloud

Skellig Michael

Skellig Michael: Flimap lidar • Range < 300m

• Altitude 40 - 400m

• 3 X 150 kHz lasers

• Scanning Angle 60°

• Accuracy (absolute)

• Horizontal ±8 cm

• Vertical ±5 cm

• Accuracy (relative)

• Horizontal ± 5cm

• Vertical ±3cm

Skellig Michael: lidar model

Sensor: FliMAP 400

(Helicopter)

Survey area: 0.3km2

GSD: 12.5cm

x,y,z first return only

Skellig Michael: lidar visualisation

South Peak

Skellig Michael

10m

5m 100m

South Peak

Skellig Michael

Monastery

10m

5m 100m

Skellig Michael: lidar limitations

Skellig Michael: TLS

• Faro Focus 120

• 48 scans (3 sessions on site,

12 hours survey time )

• Closed loop traverses

• Over 500,000,000 points

• Intensity & RGB

• VRSNOW GPS control

• Registration / Georeferencing:

Faro Scene 4.8

• Visualisation / Interrogation:

Pointools Edit (v 1.5)

Skellig Michael: lidar plan

Skellig Michael: pointcloud

Skellig Michael: Data fusion?

Flimap lidar

Faro Focus, Terrestrial laser scan

DATA

FUSION?

Conclusions / Challenges

Conclusions

• data capture on course: completion June 2014

• lots of data cleaning required

• data re-use – state agencies very interested in scientific /

promotional value of data

Challenges

• meshing complex pointclouds

• complete the pipeline – MODEL – DEPOSIT - USE

• data fusion

www.discoveryprogramme.ie

More information:

http://3dicons-project.eu/

http://www.discoveryprogramme.ie/

Contact:-

robert@discoveryprogramme.ie

anthony@discoveryprogramme.ie

gary@discoveryprogramme.ie

Thanks to:-