4D reconstruction of Fort "Rocchetta"

Hi everyone,

it's been a long time since I've written a post. Like always the problem is the lack of time :).

I will try to be more present on ATOR and reactivate our blog, since recently some people wrote me that it has been a good resource for free research in archaeology during the last years. I think that, with the help of readers and authors, the blog can start again to share interesting information about Open Research in our discipline.

Today I will start writing about the result of a study we did in 2018, for an exhibition on the World War I in Non Valley. We were asked to work on the archaeological session of the exhibition, which was held in the town of Livo. If someone is interested in this project, here is the article (in Italian), about our session: it is basically an introduction to Modern Conflict Archaeology, with focuses on the several sub-disciplines which are used in this kind of research (Aerial Archaeology, Glacial Archaeology, High Mountain Archaeology, Underwater Archaeology and Speleoarchaeology).

Working on this project, we tried, like always, to keep an Open Research approach, so that, after the good experience of the Open Source exhibition "Imago Animi", we also organized an editathon for Wikipedia, thanks to the help of the wiki community of our region. I will write in another post about this experience. Today I will share one of the main result: the 4D reconstruction of Fort "Rocchetta", which is one of the main structure of the valley, involved in WW1.

One of the view of the reconstruction of Fort "Rocchetta"

The 4D reconstruction has been performed by our 3D specialist Cicero Moraes in Blender. Technically speaking it is a synchronic 4D, since we reconstructed the building at the moment of its construction (around 1860), but we planned a future development into a diachronic 4D (with all the historical steps that modified the structure), after a more accurate research. We speak about 4D, because this kind of archaeological reconstructions are done to recover the three spatial coordinates (x,y,z, better, n,e,z) and the fourth temporal coordinate (t).

Another view of the reconstruction of Fort "Rocchetta"

Currently the fort is in the state of ruins, so that to perform the reconstruction we started with an archaeological survey on the field, integrated with an historical (archival) research, studying the documents of the Archivio di Stato di Trento and of the Österreichisches Staatsarchiv of Wien. Thanks to this research we were able to find some old pictures, and a map, showing the fort from enough different viewpoints to try a SVR (Single View Reconstruction), based on perspective rules.

If you need to use a similar technique for your work, there are several Free/Libre and Open Source Software to perform this kind of 4D reconstruction. One of the first software of this kind was jSVR, but nowadays I would suggest to use the specific Blender addon BLAM, recently evolved into the project fSpy. BTW Cicero preferred to work directly in Blender, without the use of addons.

Here below is the final video we produce, released with an open license (CC-BY).

I hope this post was useful, have a nice day!

The devils boat

This year, thanks to Prof. Tiziano Camagna, we had the opportunity to prove our methodologies during a particular archaeological expedition, focused on the localization and documentation of the "devils boat". 

This strange wreck consists in a small boat built by the Italian soldiers, the "Alpini" of the battalion "Edolo" (nicknamed the "Adamello devils"), during the World War 1, near the mountain hut J. Payer (as reported by the book of Luciano Viazzi "I diavoli dell'Adamello"). 

The mission was a derivation of the project "La foresta sommersa del lago di Tovel: alla scoperta di nuove figure professionali e nuove tecnologie al servizio della ricerca” ("The submerged forest of lake Tovel: discovering new professions and new technologies at the service of scientific research"), a didactic program conceived by Prof. Camagna for the high school Liceo Scientifico B. Russell of Cles (Trentino - Italy).

As already mentioned, the target of the expedition has been the small boat currently lying on the bottom of lake Mandrone (Trentino - Italy), previously localized by Prof. Camagna and later photographed during an exploration in 2004. The lake is located at 2450 meters above see level. For this reason, before involving the students into such a difficult underwater project, a preliminary mission has been accomplished, in order to check the general conditions and perform some basic operations. This first mission was directed by Prof. Camagna and supported by the archaeologists of Arc-Team (Alessandro Bezzi, Luca Bezzi, for underwater documentation, and Rupert Gietl, for GNSS/GPS localization and boat support), by the explorers of the Nautica Mare team (Massimiliano Canossa and Nicola Boninsegna) and by the experts of Witlab (Emanuele Rocco, Andrea Saiani, Simone Nascivera and Daniel Perghem).
The primary target of the first mission (26 and 27 August 2016) has been the localization of the boat, since it was not known the exact place where the wreck was laying. Once the boat has been re-discovered, all the necessary operations to georeference the site have been performed, so that the team of divers could concentrate on the correct archaeological documentation of the boat. Additionally to the objectives mentioned above, the mission has been an occasion to test for the first time on a real operating scenario the ArcheoROV, the Open hardware ROV which has been developed by Arc-Team and WitLab.
Target 1 has been achieved in a fast and easy way during the second day of  mission (the first day was dedicated to the divers acclimation at 2450 meters a.s.l.), since the weather and environmental conditions were particularly good, so that the boat was visible from the lake shore. Target 2 has been reached positioning the GPS base station on a referenced point of the "Comitato Glaciologico Trentino" ("Galciological Committee of Trentino") and using the rover with an inflatable kayak to register some Control Points on the surface of the lake, connected through a reel with strategical points on the wreck. Target 3 has been completed collecting pictures for a post-mission 3D reconstruction through simple SfM techniques (already applied in underwater archaeology). The open source software used in post-processing are PPT and openMVG (for 3D reconstruction), MeshLab and CloudCompare (for mesh editing), MicMac (for the orthophoto) and QGIS (for archaeological drawing), all of them running on the (still) experimental new version of ArcheOS (Hypatia). Unlike what has been done in other projects, this time we preferred to recover original colours form underwater photos (to help SfM software in 3D reconstruction), using a series of command of the open source software suite Image Magick (soon I'll writ  a post about this operation). Once completed the primary targets, the spared time of the first expedition has been dedicated to secondary objectives: teting the ArcheoROV (as mentioned before) with positive feedbacks, and the 3D documentation of the landscape surrounding the lake (to improve the free LIDAR model of the area).
What could not be foreseen for the first mission was serendipity: before emerging from the lake, the divers of Nautica Mare team (Nicola Boninsegna and Massimiliano Canossa) found a tree on the bottom of the lake. From an archaeological point of view it has been soon clear that this could be an import discovery, as the surrounding landscape (periglacial grasslands) was without wood (which is almost 200 meters below). The technicians of Arc-Team geolocated the trunk with the GPS, in order to perform a sampling during the second mission.
For this reason, the second mission changed its priority an has been focused on the recovering of core samples by drilling the submerged tree. Further analysis (performed by Mauro Bernabei, CNR-ivalsa) demonstrated that the tree was a Pinus cembra L. with the last ring dated back to 2931 B.C. (4947 years old). Nevertheless, the expedition has maintained its educational purpose, teaching the students of the Liceo Russell the basics of underwater archaeology and performing with them some test on a low-cost sonar, in order to map part of the lake bottom.
All the operations performed during the two underwater missions are summarized in the slides below, which come from the lesson I gave to the student in order to complete our didactic task at the Liceo B. Russell.

Aknowledgements

Prof. Tiziano Camagna (Liceo Scientifico B. Russell), for organizing the missions

Massimiliano Canossa and Nicola Boninsegna (Nautica Mare Team), for the professional support and for discovering the tree

Mauro Bernabei and the CNR-ivalsa, for analizing and dating the wood samples

The Galazzini family (tenants of the refuge “Città di Trento”), for the logistic support

The wildlife park “Adamello-Brenta” and the Department for Cultural Heritage of Trento (Office of Archaeological Heritage) for close cooperation

Last but not least, Dott. Stefano Agosti, Prof. Giovanni Widmann and the students of Liceo B. Russel: Borghesi daniele, Torresani Isabel, Corazzolla Gianluca, Marinolli Davide, Gervasi Federico, Panizza Anna, Calliari Matteo, Gasperi Massimo, Slanzi Marco, Crotti Leonardo, Pontara Nicola, Stanchina Riccardo

Arc-Team: Conflict Archaeology of the First World War on the Carnic ridge and in the Sexten Dolomites

With the centenary years 2014–2018, a hitherto relatively unknown branch of archaeological research, the so-called conflict archaeology, is coming into the limelight. Since  excavation work is able to supply only very selective assertions on account of the enormous extent of the mountain front, the overriding objective of monument conservation in the years to come must focus on taking stock of all material remains from the WWI era.

As a result of the developments in satellite geodesy and 3D documentation, it is now possible to approach this task on a wide scale and comparatively economically. The data collected form the basis of targeted protection measures and provide for future reference numerous new methods of presentation which fulfil the requirements of nature and monument preservation as well as the growing interest of demographic groups.

The article is illustrating the latest research results of Arc-Team and is written in German Language by Rupert Gietl. 
It was published inside the volume:
Das Pustertal und der Krieg 1914–1918 (TAP-Forschungen, Bd. 2) by the 
Tyrol Archive for Photography (TAP)

Download the article

The Austro-Hungarian emplacements on top of Mt. Roteck

(2390m)

Dolomites / South-Tyrol 

 A case study for extensive survey and documentation on occasion of the 100th anniversary of the beginning of WW1 on the Italian front in May 2015.

As reported on ATOR in summer 2013, Arc-Team is pushing ahead the plan of  mapping extensive areas of the high alpine frontline of WW1 from the Swiss border to the Dolomites.

Our approach consists in a very detailed DGPS-survey, terrestrial structure from motion, geolocalized images, archeological description and aerial survey by our drone.

Of course we are basing the whole working process on Open Source Soft- and, where possible , also on Hardware.

Now we want to share the latest version of a presentation, given originally in occasion of the 7th Fields Of Conflict Conference in Budapest (Hungary) in October 18.-21. 2012.

It outlines the characteristics of the high alpine working environment, the nature of the WW1 remains, the challenges to meet, our project strategy and first results.

WW1 - Documentation Project: New Data Aquisition Season

Finally, after a rainy spring, we are going to start a new campaign of data acquisition over 2150 m.a.s.l. along the WW1 front line. This time we will document a section of GUA10B (Grenz-Unter-Abschnitt) KAIII (Kampf-Abschintt) named Hahnspiel, a second line of austrian fortifications along the Dolomites frontline between May 1915 and November 1917.

The main innovation of this year will be the usage of our aerial drone (Naza DJI) in order to have an additional point of view in this mountainous and uneven terrain.

In addition to our traditional approach (GPS-survey, terrestrial structure from motion, geolocalized images and archeological description) we want to implemet data from aerial survey in order to create models of lager areas.

We hope to get through the summer without any crash :-) so that we could share our experience with you next autumn.

SfM for Underground Documentation

Since last October Arc-Team is working on a challenging project about World War 1 on the southwestern frontline 1915-18.

Austro-Hungarian artillery piece in wintry position 1916

In a few years we will celebrate the 100st recurrence of the Italian declaration of war against the Austro-Hungarian Empire in May 1915.
For that reason the South-Tyrolean Heritage Departement was starting an extensive archaelogical survey campaign in high alpine environment up to 3900 m.s.l.
We've had to find out a rapid, lightweight and low cost method to document the uncountable amount of structures along both front lines.
The area of our pilot project is an approximately 6 sqkm large high plane between 2000 and 2300 m.s.l. called Plätzwiese. Between 1915 and 1917 it was a strongly fortified second line artillery position of the Austro-Hungarian Army.

Crew Cavern

Because of the seclusion of this area, today there we can find some of the best preserved residues of WW1 in Europe. We expect a total amount of more than 1000 archaeological remains just in this sector.
One of the major challenges is the documentation of the numerous tunnels and caverns driven in to the rock to protect troops and material from enemy artillery fire.

View towards the exit

We apply SfM to obtain pointclouds of the interiors, dealing with difficult conditions of illumination and space. After placing GCP's around the entrance(s) and measuring them with our DGPS, we start with one or more sequences of pictures in the entrance area, advancing along the tunnels, turning at their end and coming back to the starting point.

In the dark we use of course a tripod to allow long exposures and some torches, to illuminate shadow areas.
In this way we've taken up to 300 pictures for one single structure.
Various attempts of processing them in Python Photogrammetry Toolbox divided in a few single sequences, gave us some indication of the most advantageous way of photographing.

Point Cloud in MeshLab v1.3.2.

For good results we need to follow two important rules:

1. Redundancy: The same point has to be visible in much pictures possible.
2. Long baseline: To obtain correct geometrical information, the projection centers of the sensors have not to be to close together.

• Taking a just a single photo-sequence along one way of the cavern, causes often problems with redundancy and subsequently lead to empty areas in the pointcloud, especially along the ceiling of the cavern.

Recording strategy 01

• Another of the experiences gained, is that the software has big difficulties to match features form the photo-sequence taken on the way inwards, with features from the photo-sequence taken on the way back to the entrance of the tunnel.

Recording strategy 02

• We get the best results advancing on two parallel lines, as well on the way in, as on the way out of the structure.

Final result 01

Finally we processed the parallel sequences of each direction and referenced them after in Cloudcompare in the way how Ale Bezzi described it.

Final result 02

In June 2013, after the thaw, we will resume fieldwork in Plätzwiese and we hope to  acquire further experience.