Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Methodological contest between high-end hardware and low-cost equipment for archaeological documentation keywords structure from motion, image-based modeling approach, 3D geo-spatial field technology, archaeological data acquisition, 3D laser scan, FOSS, GRASS GIS, high resolution digital documentation technique Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz

Introduction-> Research question, State-of-the-art of digital documentation methods Introduction-> Research question, State-of-the-art of digital documentation methods Aim-> Comparison of two methods Aim-> Comparison of two methods Case study-> Ostia Antica Case study-> Ostia Antica Results-> And the winner is …! Results-> And the winner is …! Outlook-> Future perspectives Outlook-> Future perspectives

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Research question

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook State-of-the-art of digital documentation methods in Prehistoric Archaeology First application of terrestrial laserscanners in Prehistoric Archaeology by VIAS Wien Quelle: VIAS Wien ©VIAS Vienna

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook State-of-the-art of digital documentation methods in Prehistoric Archaeology First application of terrestrial laserscanners in Prehistoric Archaeology by VIAS Wien (© ArcTron)

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Advantages & Disadvantages -High quality and precise documentation -immediate control -Hardware: quick and easy to use -Software: can be operated intuitively after an introduction -Fast and easy referencing and geo- referencing possible -Fast data processing = data preparation -Time consuming because of mostly more than one scanworld is needed -Every scanworld needs a new registration by scanning all targets = time consuming -Hardware: havy equipment -Difficult custum regulations in certain countries -Very expensive equipment -Software: Very expensive proprietary for documentation and first data preparation

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook State-of-the-art of digital documentation methods in archaeology Computer Vision / Structure-from-motion - originally developed for Tourism / Social networking purposes - Online-Services like Photosynth or Photofly for all all kinds of use: private, construction, forensics, design… -> ca. 150 industries using it (NY Times)

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Computer Vision / Structure-from-motion - Adaption for archaeology as a low-cost alternative to laser scanning - different packages available: -Proprietrary: Photoplan, Arctron aspect3D - Open source: ArchOS, BundlerTools, VisualSFM

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Advantages & Disadvantages Advantages: - little gear - low-cost - time-saving (on-field) - more weather resistent - flexible

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Disadvantages - spatial cover - post-processing (Workflow) - no immediate control - required compute power (but no cloud-computing necessary)! - georeferencing Advantages & Disadvantages

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Comparison of two methods LaserscanningStructure-from-Motion Hardware PriceHighLow TransportHeavy and difficultJust one photo camera ist needed Additional Equipment + Tripod, + Notebook, + certain targets No Power supplyNeeded Acquisition time6x as long as SfM Workflow steps distance, spatial cover The longer the distance, the lower the resolution. field of application Architectur, Prehistoric Excavation. Weather sensibility 40 Not applicable by rain and temperature higher 40°C and lower – 40°C. Handling managementDifficult to handle Software Pricehigh Usability can be operated intuitively after an introduction Maintenance Processing time Post-processing

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook OfficeFreyenstein Ostia Antica

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Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz vertices Laserscan (resolution 1 mm, 1 Scanworld) Structure-from-motion vertices

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Ostia Antica Taking pictures: easy Taking usable pictures, some things to think of: Good camera objective helps large memory cards necessary Don´t forget targets for measurements and color balance more cameras would even speed up assure the overlap! Laptop on site for instant check of photos and running of small models Data acquisition of structure from motion

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Ostia Antica Open-source: bundle of software needed: Image viewer/Graphics software-> sort / rename images Linux: BundlerTools-> create pointcloud Meshlab, CloudCompare-> clean pointcloud, pick points NEW: GRASS GIS:.ply-Import/Export module + georeferncing (rectify) Paraview, (AutoCAD), Meshlab, CloudCompare, Blender-> analyzing

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz

3D Georeferencing application flow: 1) Import of the point cloud in different file formats: e.g. PLY, LAS PLY Vertex-attributes included v.ply.in 2) Georeferencing of vectors in GRASS GIS v.transform 3)Export of the point clould in different file formats: e.g. PLY, VTK v.ply.out Maximum size of the pointcloud: 2 billion points

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz 3D Georeferencing Affine and higher polynomial transformation based on control points The accuracy of the transformation is depended on the accuracy of the control points Affine transformation: For each dimension separately: move, scale, rotate Helmert-Transformation (coming soon!): For each dimension separately: move, rotate For all dimensions equally: scale

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook And the winner is …!

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz Introduction Introduction Aim Aim Case study Case study Results Results Outlook Outlook Future perspectives Computer Vision / SfM (Open-source) Toolchain from digital images to georeferenced 3D-model available Things to improve: Usability of software packages - automatic target detection Database connection

Undine Lieberwirth, Bernhard Fritsch, Markus Neteler, Markus Metz

Co-operation between the Excellence Cluster TOPOI Berlin/Germany and Fondazione Edmund Mach – Research and Innovation Centre Trento/Italiy THANK YOU FOR YOUR ATTENTION!