ATOR (Arc-Team Open Research).
The blog spreads tests, problems and results of Arc-Team research in archaeology, following the guidelines of the OpArc (Open Archaeology) project.
Showing posts with label underwater archaeology. Show all posts
Showing posts with label underwater archaeology. Show all posts
Since 2017 we are with Marco Block Berlitz and Moritz Mennenga to organize a session about underwater archaeology during the annual conference Cultural Heritage and Newt Technologie (CHNT), held in Vienna.
This short post is to report that, thanks to the effort of Susanne Uhlirz and Wolfgang Börner, the proceedings of the 22nd conference are now online. This is the direct link to proceedings, while, if you are interested in our contribution ("Documentation and sampling strategies in underwater archaeology. General criteria and specific solutions"), you can read here.
The first slide of Arc-Team's presentation at CHNT 2017
this second, brief post is intended to share other open data regarding our underwater archaeology mission in the inland waters of Trentino (Italy).
As you know, this summer, we joined the exploration of the lake Monticello (almost 2600 m asl, near Paradiso Pass), looking for evidences of the WW1 in the Adamello front. If you missed the post, I described here the new methodology we used to achieve a complete 3D bathymetric chart, using just a low-cost sonar sensor. Today I just uploaded on our server the 3D data, so that other researchers can use them, if they will find them of some interest.
Here below I post a screenshot of the data loaded within +QGIS:
The bathymetric chart of Lake Monticello
Here is possible to download the 3d bathymetric chart of Lake Monticello. As always the data are available with the following license:
it has been a long time without post here in ATOR, but this year we had to work on several different projects, without the possibility to report fast feedback in our blog.
I start today to write again, due to the fact that some of these projects grab the attention of different institutions of the academic world and, in particular, this happened for our underwater archaeology missions.
Of course our primary interest during our diving is related with the archaeological perspective, but often the data we collect can be useful for other specialists (e.g. limnologists or biologists).
This is the reason why we decided to share our data and we start today with the bathymetric chart of Lake Tovel (previous post in ATRO: 1, 2). I processed this map working on the Red Lake Project, a research, directed by Prof. +Tiziano Camagna, which tries to study the medieval submerged forest of Lake Tovel (Trentino - Italy). I produces a 3D model of the bathymetric chart of this lake directly digitizing the map of Edgardo Baldi did in the '30s. Than I calibrated the result with the LIDAR model of the landscape, freely accessible form the geographic open data portal of the Autonomous Province of Trento (here a short tutorial about how to download data from the webgis).
Here is possible to download the file (an ESRI ASCII grid), ready to be integrated in most of the GIS software (below a screenshot of the data in GRASS GIS).
Tovel Lake bathymetrci chart in GRASS GIS
The data are available under the following license:
as you see we are writing few post in ATOR in the summer season, due to different field projects which take us away from home. Today I try to start again to dedicate some time to our research blog.
The topic of this post regard a solution we are currently using to help us in the archaeological exploration of high alpine lakes: the documentation of the bathymetry through a low cost sonar.
As you maybe know, since a couple of year we are working on underwater archaeology projects in the alpine lakes of our region (here an example). This kind of exploratory mission are difficult, due to the altitude of the site we have to investigate (almost always over 2000 meters asl), so that our divers have to acclimate themselves for one whole day, before starting the working. Also for this reason we started again to study archeorobotics and develop, together with our friends of the WitLab, an open hardware ROV called ArcheoROV (in order to help divers in exploratory mission).
The ArcheoROV (photo by WitLab)
This year we focused or research in find a cheap solution to map the bathymetry of the lakes, while WitLab went on working on the Wi-Fi buoy which gives our ROV a long-range operability (respect the limitation of a simple control on shore). For this reason we tested a cheap sonar called Deeper, which normally is used as a fishfinder.
We started our test in the Lake Tovel, thanks to the hep of Prof. +Tiziano Camagna , who is leading the exploration project since many years. This lake is almost our playground to develop and test new solutions for underwater archaeology, since it is a difficult environment, but not extreme (like other high mountain lakes). We chose this location also because, on unlike other lakes, its bathimetry was documented by Edgardo Baldi in the 30s. We already digitized this map, processing a 3D model in GRASS GIS, so that we have some data to check our results with our small sonar (as you can see in the image below).
On the left the map drawn by Edgardo Baldi between 1937 and 1938; on the right the 3D derived map developed by Arc-Team in GRASS GIS
Some more details of the 3D map developed with GRASS GIS
To test the Deeper sonar, Porf. +Tiziano Camagna designed a small buoy which can be towed by a kayak. This solution stabilize the sonar (which remain always in the right position) and, at the same time, avoid its submersion (which causes the lost of the GPS signal).
First positive results (image below) encouraged us to use this solution on a real mission, at the Monticello lake (almost 2600 meters asl), at Paradiso Pass (near Tonale Pass, Trentino, Italy).
A comparison between the digitized map of E. Baldi (on the left) and the map (work in progress) obtained with the Deeper sonar (on the right)
The expedition was joined also by our friends of the Team Nauticamare (Massimiliano Canossa and Nicola Boninsegna) and gave us the opportunity to accomplish a first mapping of the Lake Monticello, during the first day of acclimatization. This helped us very much during the archaeological underwater mission of the second day. As a result we have now a good 3D map of the bathymetry of the lake, which we will use also in the next expedition (September 2017). Her below is a short video (done with +QGIS plugin qgis2threejs), which shows the 3D model of the lake.
PS
I recorded some videotutorial related with the processing of these data. I will try to upload them ASAP in our channel.
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
We have recorded hours of movies during our diving project in the Mandrone lake.
Later this year we will publish a video illustrating us while we are working over and under the water surface.
In the meantime we want to whet your appetite with just a few pictures...
Enjoy!
On August 25th and 26th 2016 a team of divers and archaeologists has explored the bottom of lake Mandrone (2.409 m.a.s.l.), Adamello Alps/Italy. Under the direction of prof. Tiziano Camagna, the team has localized and documented the wrack of a boat build there during World War I.
Team-leader Tiziano Camagna was supported by the archaeologists of Arc-Team Ltd. (Cles/Sexten – Italy), Alessandro Bezzi, Luca Bezzi and Rupert Gietl. Massimiliano Canossa and Nicola Bonisegna, underwater-experts from NauticaMare DiveTeam, have realized high-resolution videos and photos.
The main target of the mission was the localization and documentation of the wooden remain on the ground of lake Mandrone. The boat was build between 1916 and 1918 and sank some years after the end of WW1. Pictures and videos taken by the divers will now be processed by the archaeologists in order to extract a detailed 3D model using Computer Vision technologies like SfM (Structure from Motion) and MVS ( Multiple View Stereovision).
Tiziano Camagna first localized the remain in 2003, comparing it with two historical photos published by Luca Viazzi in the volume "I diavoli dell'Adamello - 1915 -1918 La guerra a quota tremila". The first shot is showing Italian mountain troops (Alpini) building a boat near the “Julius Payer” refuge, situated about 800m northeast from lake Mandrone. The second Capt. Castelli rowing on the lake.
The Adamello Alps have been one of the highest war theaters of WW1. In the area around lake Mandrone and the refuge “Città di Trento” we can still find lots of archaeological remains of that period: Trenches, barracks, observation positions and a small military cemetery.
Austro-Hungarian and Italian troops had not only to fight against each other, but primarily against the harsh climate on altitudes up to 3.900 m.a.s.l., 10-12 meters of snow in the winter and temperatures right down to -30°C (-10°F).
Thanks to the support of the wildlife park “Adamello-Brenta” and the Gallazzinis, tenants of the refuge “Città di Trento”, the equipment of our expedition was transported on site with the goods cable lift of the refuge. The team went up by foot, walking about three hours starting at the head of “Genova” valley. On the last stage, from the refuge to the lake, the gear was carried on the back.
In order to facilitate the transport, divers choose light equipment like the sidemount system.
During the dive our photographer Nicola Boninsegna localized a wooden trunk on the ground, a discovery that gives rise to some new research questions, considering the total absence of trees on that altitudes.
The find will be analyzed soon, in order to get dating and identification of the species.
This mission was also an opportunity for a high altitude test of our ROV prototype (Remotely Operated Vehicle), named ArcheoROV developed by WitLab laboratories from Rovereto, in collaboration with Arc-Team.
Last but not least the team wants to thank the Department for Cultural Heritage of Trento (Office of Archaeological Heritage) for close cooperation.
As you probably noticed, one of the topic of ATOR is related with hardware hacking, with the aim to build new archaeological devices from ordinary objects and tools (33).
This concept is close to the one of "reuse" (using an artefact for a purpose which is completely different from the original function), a pretty common phenomenon in archaeology; also in architecture there is something similar, called "spolia" (but maybe our interest in hacking things is just a kind of McGiver syndrome of people grown up in the 80s).
However, this post is about hacking a common game device like Kinect to use its characteristic in archaeological 3D real-time documentation. If you are a regular reader of ATOR, you will know that we already face this challenge, performing a first test (1) with RGBDemo in February 2012, and controlling accuracy and precision of the device in March of the same year (2), after a discussion with some of the researchers of FBK, during the workshop "Low cost 3D: sensori algoriti e applicazioni". Due to the encouraging results achieved in our first experiments, we worked on the hardware in order to modify it for outdoor projects (3), but soon we experimented the limits of this technology when applied in areas with direct sunlight (4) or in documenting small objects (5, 25). Despite this drawbacks in our research, Kinect worked pretty good in indoor excavations (6), helping us in difficult situations (related with the the workplace safety), and for particular purposed, like for infra-red prospections in dark environment (7).
After all these experiences, our final advice about Kinect is that the device has a potential in archaeology, but its real employment in professional work is restricted to peculiar conditions, while in most of the cases the SfM-based techniques are the best option (due to their versatility, which makes them a perfect choice during missions abroad (8), for small finds documentation (9, 10), for underwater and aerial archaeology (11, 12, 13), considering also the speed which characterize SfM and MVSR open source software development (14) and the wide range of possibilities between the different tools (15, 16).
Well, at least this was our opinion until now... Currently we are changing our mind about Kinect, and this is due to our professional engagement in underground archaeology (17) and to our renovate interest in robotics. Let's deal with these two points separately.
Underground archaeology
Documenting an underground semisubmerged structure in Firuzabad (Iran)
Like any other operation in archaeological 3D documentation, the tolerance regarding accuracy and precision is variable and influenced by some factors, and mainly: research purposes, logistics, characteristics of the structures to be documented.
Without considering some important exceptions (e.g prehistoric rock shelter, which are often simple to document with SfM techniques), most of the structures related with underground archaeology (WW1 artificial caves, medieval mines, etc...) are connected with large scale survey projects (where it is important a "big data" approach, raising the tolerance in data acquisition to increase the number of documented structures); with logistically difficult areas (high mountains, glaciers, (18, 19) etc...); with structures often characterized by vast surfaces without important small details, which (when present) can be recorded with a targeted SfM or RTI (21, 22) documentation (e.g. for graffiti, inscriptions (20), manufacture traces, etc...). For this reason, in most of these projects, it is necessary to deal with precision in documenting (keeping checkpoints thanks to other TOF instruments, like total stations) in order to gain a real-time response from the selected device, and, under this point of view, Kinect is often a good solution, considering also that its infrared sensor helps very much in low light conditions (7).
Documenting WW1 caves in Southtirol (Italy)
Archeorobotics
Arc-Team's UAV during an aerial archaeology project in Storo (Trentino - Italy)
Since 2006, when we joined an aerial archaeological project in Armenia (23), we started to work on "archaeorobotics", trying to develop robotic devices able to help us in the most difficult archaeological missions.
The first positive results we reached in this field were related with aerial archaeology and the building of an open hardware UAV (in 2008), even if at the beginning we underestimated the time needed to practice with our new tool (24). Soon our experience increased as we built different drones, based on open and closed solutions (like kk multicopter (26) or Naza dji (27) models). The benefits of this research branch were clear (28, 29) and soon other research institutions, like the CNR-ITAB of Rome (30), the University of Lund (31) and the CNR-ISTI of Pisa (32), asked us to give lessons about this topic.
Another field of archaeorobotics we explored is the one related with CNC machines and especially with 3D Printers. For this topic a precious help came from the society Kentstrapper and Leonardo Zampi (aka +Exekias 87), who helped us in 3D printing the cast of the Taung Child (34, 35). Since RepRap project started (in 2005), 3D printers evolved very fast. Of course our interest regarding these machines is mainly oriented to Cultural Heritage, and this is also the reason why we built a Fa)(a 3D form scratch (36), but results with this kind of instruments can be very impressive, especially considering the wide range of scientific applications (37, 38, 39, 40, 41), even if sometimes you have to deal with difficult boolean operations (42).
However, none of the robotic projects we developed till now needed Kinect, being based on UAV, to 3D document archaeological sites, or on CNC machines, to fast replicate archaeological artefacts. Our renovate interest in Kinect for archeorobotics is due to our new challenge in developing a ROV (Remotely Operated Vehicle), in order to assist us in our underwater archaeological missions. Indeed, in the last months, we started a collaboration with the WitLab, the FabLab of Rovereto (Trentino - Italy), to develop a new Open Hardware ROV, especially designed for archaeological aims. One of the main topic in developing such an instrument is that the new robot will be oriented not only to 3D documentation, but also to the exploration of unknown areas. For such reason SfM and MVS software are no more enough, but we had to start again in testing Open Source SLAM (Simultaneous Localization And Mapping) algorithms, due to the fact that we need to register in 3D the submerged landscape (Mapping), but also to recover the path the "ArcheoROV" did (Localization) to reach new hidden archaeological evidences (for a better planning of human operations).
Testing the ArcheoROV at night
Testing Open Source SLAM solutions
The importance of SLAM algorithms in exploring devices is the main reason why we started again to experiment Kinect. Indeed, despite Kinect cannot be used as an on-board optical device in our ArcheoROV (due to the infrared camera), this tool is the perfect system to check SLAM software.
If, you ever started in working on robotics, probably sooner or later you stepped into ROS (Robot Operating System), an Open Source (BSD License) collection of software frameworks for robots. Of course SLAM is a very important task for any robotic vehicle, and the ROS package RTAB-Map is a perfect solution to implement this capability into any autonomous or remotely operated machine, like our ArcheoROV. For this reason, before starting experiments in more sophisticated (and complicated) systems, we checked RTAB-Map performance with an old Kinect, and here is the video of the result:
As you can see, the performance of real-time 3D is pretty responsive, respect our old experiments with the Open Source software RGBDemo (also considering that the Kinect used in this video is the first version, and it is now pretty obsolete) and, most important, the localization function within SLAM algorithm works very good. As I wrote at the beginning of the post, our current impression is that this combination of hardware (Kinect) and software (ROS) can be a good solution for underground environment documentation, while the software can be the right choice for archaeological exploring robotic devices.
I hope that this long post will be useful, if you have any feedback, please just write your comment below. Have a nice day!
PS:
we will present the ArcheoROV at the ArcheoFOSS (43) of Cagliari (Sardinia - Italy), this year. Also our partner of WitLab will be with us!
It is long that Alessandro and me wanted to write this post, but for one reason or another, we could not work on it.
Today I decided to do it in order to answer two questions that people often asked us during conference or lessons:
1) Is it possible to work with SfM/IBM techniques underwater?
2) Is it possible to extract 3D from a movie?
As regards the first question, I can report that since we (Arc-Team) started to work with SfM and IBM (2009), we did also tests underwater and they gave us positive results. This is one of the main reason why we invested so much time on the researchin this filed: SfM and IBM methodology, until now, is one of the best solution in archeology, due to its versatility (it can be used for underwater or aerial documentation, in low light conditions or in precarious situation, during mission abroad, etc...). We already underlined this concept when, with the help of Nicolò Dell'unto (Lund University), we compared different methodology to record 3D documentation of archaeological artifacts. The result of this experiment was presented during the ArcheoFOSS 2012, in Napoli (see the related slides and this post). During the workshop "Low cost 3D: sensori, algoritmi e applicazioni", we had the opportunity to better analyze the use of SfM/IBM in extreme working conditions, strengthening our point of view about this methodology (see the related slides). The image below is an example of an aerial 3D documentation done with an open source UAV and Python Photogrammetry ToolboX...
Aerial documentation with a KKopter and ArcheOS (PPT)
... while this other image shows the results we achieved using some pictures that Victor Jansa, of TUWA ("Tauchverein für Unterwasserarchäologie"), sent us to do a test.
Test with Victor Jansa's pictures (done with PPT)
In order to answer the second question, I can say that, facing our experience, it is possible to reconstruct 3D models from videos (and I guess this is one of the aims of SfM itself). We did some tests about this topic, getting acceptable result (at least regarding our primary target, which was to have a fast 3D object for further modeling operations). As an example, I can report one of the last post of Cicero Moraes, who used SfM from a youtube clip to get a 3D skull for forensic facial reconstruction aims. The image below is taken from Cicero's photo album:
3D skull obtained with SfM techniques from a movie
For a better explanation of what I wrote above, I think it is worth to show the results of a project we are undertaking since 2005 (trying to support Prof. Tiziano Camagna on his exploration of Tovel's Lake, in Trentino). During this project we did several surveys, diving in different parts of the lake and especially in the South-West area, where lies a forest which is now underwater. In 2012 Tiziano Camagna and Andrea Forti, despite the low visibility, where able to record a short movie of some of the threes. We used this video for a fast 3D reconstruction, because it was particularly indicated, due to its characteristics: it was recorded for no SfM aims (as you see the movie sequences are not optimal for a 3D reconstruction), it represents the normal turbidity condition of the lake and it was done with an high lens distortion camera (GoPro Hero 2). For such reasons this material was perfect to hardly test SfM and IBM techniques for underwater archeology. In this animation you can see a short part of the movie (from the 15th second to the 25th), which we used for the 3D documentation...
From "La foresta sommersa del Lago di Tovel" (T. Camagna, A. Forti)
... and here you can see the result:
I hope this post was useful. Soon, when the season will allow us to start diving again, we will go on with tests and experiment related with underwater archeology. I hope to write soon some new report about it.
Since 2005 we tried to support Professor Tiziano Camagna and Andrea Forti effort in investigating the underwater forest in Tovel Lake. A preliminary report and some results have been publish in the magazine "L'eco delle Dolomiti". Hopefully this interesting project will go on in the next years: it is also a perfect playground to test new techniques of documentation for underwater archaeology.
Tiziano Camagna, Alessandro Bezzi and Luca Bezzi before the dive
