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

ArcheOS Hypatia, a new tool for 3D documentation: opnMVG-GUI

In these days we are working very hard to package new software for ArcheOS v. 6 (codename Hypatia). This time we just finished to work on the new GUI +Martin Greca developed for +Pierre Moulon software, openMVG, setting up all the requested dependencies. The result is a new tool for 3D photogrammetry in +ArcheOS: openMVG-GUI. This software can be considered as the evolution of the old Python Photogrammetry ToolBox, but we are currently working to fix some bugs of this application to keep providing it in ArcheOS, since it gave the best results in underground environment documentation.

Here below you an see a fast videotutorial I did for our brand new YouTube channel:

To speed up ArcheOS Hypatia development, we set up an unofficial new repository, which we will use (by now) just internally our society, to be sure that everything works fine before to release it publicly to all the users. Anyway we will share this repository also during the university courses in which we should teach this years, like the one in Evora (Portugal) or the one in Venice, since in this conditions it is possible to work under strict control, avoiding problems in unresolved package dependencies. As soon as the new repository will be hardly tested, we will open it, adding the coordinates to the ArcheOS main branch.

The new GUI (by +Martin Greca) for openMVG (by +Pierre Moulon)

 

PS

If you are interested, there are still available places for the course in Evora (regarding open source technologies and cultural heritage). Here more infos.

Have a nice day!

Documentation of a bas-relief on a cliff : the workflow

This summer, between May and June, we worked for a joint mission, led by the University of Innsbruck (Institut für Alte Geschichte und Altorientalistik) and the Cultural Heritage, Handcrafts and Tourism Organization of Iran. The project was held in Firuzabad, in the Pars Province of Iran. We will write more details about this work in the next post. By now I just want to use some material we collected to illustrate the work-flow in data acquiring during an archaeological documentation of a bas-relief on a cliff.

The video below shows the overall process.

You can see the initial preparation phase (1), during which we placed the Ground Control Point (GCP) to perform normal 2D vertical photo-mapping and to rectify and georeference the 3D point-cloud. Than (2) we collected pictures with three different flights of our DIY drone, in order to use them with different open source SfM/MVSR software (PPT, openMVG and MicMac), to reach the best possible result: a couple of flights with parallel camera, to have a good superimposition of the whole bas-relief, and a higher acquisition to cover the upper details. In the meantime (3) another operator (+Rupert Gietl) was collecting pictures from the ground, to register also the lower perspective. Later (4), I prepared the total station and collected the GCP, thanks to some fixed points we placed the day befor (0) with our GPS. Finally +Rupert Gietl  took the last (very close) details photos, using a ladder.
The entire process lasted more or less four hours, but we needed some more time the day before to place the fixed GCP down in the valley (in international Geographic Coordinates System). A good part of the work involved just the logistics or the approach to the site, and has been slowed by the transportation of the necessary equipment (ladder, total station and drone) through a couple of passages where it was necessary to climb some rocks.
It is interesting to note that it would not have been possible to accomplish this mission with a commercial drone, due to the embargo rules (which are currently under revision), while with a DIY hexacopter it has been simple to disassemble the components which were not allowed (like the FPV system ore the GPS controlled flight).
I hope this post was useful, have a nice day!

Forensic Facial Reconstruction, the state of the art

As many of you know last week a team of the University of Leicester have publicly revealed to have discovered, in all likelihood, the tomb of Richard III. The results seem comforted by the analysis of mitochondrial DNA, while the discrepancy on the Y chromosome could be explained by a false paternity. The study was completed with a forensic facial reconstruction of the king, performed by the experts of the University of Dundee, led by Caroline Wilkinson, Professor of Craniofacial Identification.

Given the opportunity, I decided to publish here our state of the art on this particular field (forensic facial reconstruction applied to archeology), publishing the presentation that I gave during the study day in honor of Prof. Franco Ugo Rollo (Ascoli Piceno, November 26 2014).

You can see the presentation here below (better visualized at this link)...
 

... and here is a brief explanation of each slide:

SLIDE 1

A remember of Franco Ugo Rollo, professor at the Camerino University. It was not my fortune to know personally Prof. Rollo, but his name is surely well known also in my discipline (archeology).

SLIDE 2

"Digital faces: new technologies for the forensic facial reconstruction of the historical figures".
The presentation intend to be an overview of the digital methodologies of FFR with FLOSS, developed in the last two years on the blog ATOR with a spontaneous contribution of different authors.

SLIDE 3

The traditional work-flow involves several operations: 3D scanning the skull, preparing a replica, performing the anthropological analyses, placing the tissue depth markers, reconstructing the profile, modeling the muscles and skin, calibrating the model with the available sources and dressing it.

SLIDE 4

The same operations are necessary for the digital work-flow. Our main work has been to turn the traditional process into a digital one, using only FLOSS.

SLIDE 5

There are different technology to obtain a 3D digital copy of the original skull. The main two we are using are: SfM - IBM and X-ray CT.

SLIDE 6

IN 2009 Arc-Team perform the first test in applying SfM - IBM with FLOSS to Cultural Heritage, during its participation at the TOPOI excelent cluster of Berlin.

SLIDE 7

The test developed in a collaboration with the French researcher +Pierre Moulon (Université Paris - Est and Mikros Image; actually at Acute3D) to integrate SfM - IBM software in ArcheOS 4 (codename Caersar)

SLIDE 8

The first test (TOPOI Löwe) gave positive results

SLIDE 9

The process is mainly based on different photos with different orientations, computing the displacement of common points between images

SLIDE 10

To complete the 3D documentation of an object, the next step is the so-called mesh-editing, which can be performed in the software MeshLab (developed by the Visual Computing Lab at the ISTI - CNR of Pisa, Italy)

SLIDE 11

In order to validate the digital method of FFR, some unconventional procedures (derived from the hacker culture) have been adopted. With reverse engineering techniques, based on SfM, it has been possible to digitally replicate the process of past FFR projects and to compare the results.

SLIDE 12

The anthropological validation has been performed comparing the result of 3D models obtained with SfM - IBM and the relative results coming form 3D scan (the observed distortion remained in the range of 1 mm).

SLIDE 13

In several projects it is possible to work with DICOM data. In these cases the anthropological analysis is more accurate. (3D VS Voxel)

SLIDE 14

The main software we used for DICOM data is InVesalius, mainly developed at the Renato Archer Information of Technology Center, an institute of the Brazilian Ministry of Science and Technology.

SLIDE 15

"X-ray computed tomography (X-ray CT) is a technology that uses computer-processed X-rays to produce tomographic images (virtual 'slices') of specific areas of the scanned object, allowing the user to see inside without cutting." (Wikipedia)

SLIDE 16

Also in this case, the process was validated with unconventional procedures derived from hacker culture. With reverse engineering of CT videos it has been possible to rebuild DICOM data and the 3D model of different skulls, replicating FFR projects and comparing the results.

SLIDE 17

It is necessary to check and validate the protocol with a continuous methodological comparisonwith all the available resources. For this reason, we tried also the FFR of Henry the IV, a project in which Prof. Rollo was involved, rejecting (with other scholars) the attribution of the mummified head to the French king. Our test in this case is just an experiment, starting from low quality data, but it is a good example to show some benefits of digital FFR, like the possibility to quickly modify the reconstructed face (e.g. closing the mouth in order to perform superimposition with the death mask), an operation not so simple with tangible models.

SLIDE 18

Once obtained the 3D model, digital anthropological analyses do not differ from traditional ones.

SLIDE 19

In some cases, a virtual restoration of the model is necessary. The solution comes from symmetrical and boolean operations of 3D modeling software (Blender).

SLIDE 20

The whole process of 3D modeling is actually performed in the software Blender.

SLIDE 21

The first operation is to fix the 3D skull on the Frankfurt plane, which replicates the head position of a standing human figure.

SLIDE 22

Than tissue depth markers are placed. The software keeps automatically the correct normal of each marker.

SLIDE 23

In our works, for depth tissue markers, we use the tables of Degreef et alii (2006)

SLIDE 24

A second step is the profile reconstruction.

SLIDE 25

For nose shape we refer to G. Lebedinskaya method.

SLIDE 26

The validation of the method came mainly from the comparison between FFR models and the facial DICOM data of living people, a simple simple with digital techniques, using the software CloudCompaer. All this experiment were conducted ans blind test (the artist did not know the identity and the fisionomy of the people).

SLIDE 27

According to the blind test, main deviations were detected on the cheeks.

SLIDE 28

Like other 3D operations, muscles modeling has been performed in Blender.

SLIDE 29

The technique hes been continuously rationalized and optimize. For instance, once the main muscles are modeled with metaballs in Blender, the result can be reused in successive reconstructions through an anatomical deformation.

SLIDE 30

It is possible to reach more realistic results through specific modeling tools,
like the "sculpt mode" in Blender.

SLIDE 31

Also skin modeling is an operation to be performed in Blender

SLIDE 32

Again the technique has been optimized: In order to simplify and speed up the process, a neutral facial model has been  created.

SLIDE 33

The neutral model can be anatomically deformed on different skulls to meet gender and age dimorphism.

SLIDE 34

At the same time, the neutral model can be deformed to meet the anatomical criteria which determine the individual dimorphism.

SLIDE 35

After the reconstruction process, two main models are defined:  one with hair and one hairless.

SLIDE 36

Thanks to the latest developments of the software MakeHuman it is now possible to further simplify and speed up the technique. Our actual research is following this direction.

SLIDE 37

The first tests carried out in 2014 have yielded positive results, thanks to the new feature which loads base raster images. The software is also perfectly compatible with Blender.

SLIDE 38

A further development of the protocol will allow to obtain high quality forensic facial reconstructions, in less time, without the need to master the techniques of 3D modeling.

SLIDE 39

At the end of the FFR process, the final model is calibrated with historical, archaeological and medical sources.

SLIDE 40

In case of historical reconstructions, the model appearance (hairstyle and clothing) is calibrated depending on era and culture, while the physical characteristics (color of hair and eyes) are set basing on the ancestry.

SLIDE 41

The 3D printing technologies allow the materialization of the model with different levels of detail.

SLIDE 42

A case study: the forensic facial reconstruction of St. Anthony of Padua 

SLIDE 43

The 3D scan was carried out on the bronze cast performed by R. Cremesini in 1981.

SLIDE 44

The cast done by R. Cremesini is very important, because it derives from the temporary anatomical reconnection of the skull and the jaw, which were separated since the first survey of the tomb (1263). 

SLIDE 45 

3D scan has been performed with the SfM - IBM software of the archaeological GNU/Linux distribution ArcheOS.

SLIDE 46

The final model has been presented Tuesday, June 10 at the event "Scoprendo il volto di Antonio" at the Centro Culturale S. Gaetano in PAdua (Italy)  

SLIDE 47 - 50

Digital FFR allows to further define the details of the model to reach a more realistic result.

SLIDE 51

Thanks to the collaboration with the Centro de Tecnologia da Informação Renato Archer - CTI (Ministério da Ciência and Technology do Brasil) the model was printed in 3D.

SLIDE 52

One of the materialized models was repainted by the Brazilian Mari Bueno,
specialized in religious art.

SLIDE 53

Thank you for your attention!


 

Aerial images and videos of the WW1 trenches along the border between Austria and Italy

Hi all,

in the first days of October 2014, after a rainy summer, we have been engaged in taking aerial pictures and videos of the WW1 trenches in the border between Austria and Italy (villages of Kartitsch, Sexten/Sesto Pusteria and Comelico Superiore). The work was insert into a survey project financed by INTERREG funds. The trenches and military structures in the area of the project were mapped using a GPS (Trimble 5700); the most important and better preserved buildings were documented using different software (PPT, MicMac and OpenMVG) and particular hardware (aerial drone).

Thanks to Walter Gilli, our "flight instructor and drone developer", we have a new hexacopter that you can see in the picture below.

The main components are:

- a DJI NAZA-M V2 as flight controller

- a Spektrum DX8 as radio control

- a Sony Nex-7 as camera (24.3 megapixels)

- a StratoSnapper2 for the remote control of the camera (radio/IR)

- an Alexmos Gimsbal controller (2 axis) to stabilize the camera mount

- all mounted on a handmade frame

The video below shows the hexacopter flying in windy conditions. The high quality of the components makes this hexacopter a perfect instrument even in extreme situation.

The video below shows the a flight in optimal condition: a cloudy day without wind. The gimbal stabilizes the camera even during movements, ensuring a high quality result.

MicMac and PPT: two FLOSS solutions for 3D data

Hi all,
last week I finished my lectures in the Master Open Techne about Free Software and 3D data (acquisition and processing). As last year I could spend many times to research new solutions and test some applications. Some months ago, thanks to the friend +Romain Janvier , I was introduce to the use of MicMac, a suite for three-dimensional documentation of reality developed by the Institut national de l’information géographique et forestière (IGN). As Python Photogrammetry Toolbox, MicMac can produce point cloud from set of photos. There are two different ways to acquire images:

- the ground geometry mode (useful for zenithal pictures as a drone data-set or for wall's prospect) = take pictures perpendicularly to the surface (ground or wall) with 60 % of overlapping (between images and lines of image)

- the image geometry mode (useful for any kind of object that has more than one surface) = take a "cross" of images starting from the central one and then up, down, left and right; then take other images moving to the second position (frontal to another surface) and again a "cross" of image; go on in this way for all the surfaces of the object that you need to reconstruct.

The data acquisition is a little bit more complicate than PPT, both in the way to shoot and in the camera settings (keep the same level of zoom, no auto-focus, no stabilization, no flash, ...), but the final point cloud is denser. PPT is more user-friendly (thank to the python scripts and the GUI) but slower in processing data (mostly in the Camera Pose Estimation step of Bundler).

One of the advantages of MicMac is the fast developing that is improving the software and simplifying its usage. I'm waiting for the GUI ;)
Unfortunately Bundler and CMVS/PMVS have not new release since years.

From drone-aerial pictures to DEM and ORTHOPHOTO: the case of Caldonazzo's castle

Hi all,
I would like to present the results we obtain in the Caldonazzo's castle project. Caldonazzo is a touristic village in Trentino (North Italy), famous for its lake and its mountains. Few people know about the medieval castle (XII-XIII century) whose tower is actually the arms of the town. Since 2006, the ruins are subject to a valorization project by the Soprintendenza Archeologica di Trento (dott.ssa Nicoletta Pisu). As Arc-Team we participated in the project with archaeological field work, historical study, digital documentation (SFM/IBM) and 3D modeling.
In this first post i will speak about the 3D documentation, the aerial photography campaign and the data elaboration.

1) The 3D documentation 

One of the final aims of the project will be the virtual reconstruction of the castle. To achieve that goal we need (as starting point) an accurate 3D model of the ruins and a DEM of the hill. The first model was realized in just two days of field-work and four days of computer-work (most of the time without a direct contribution of the human operator). The castle's walls were documented using Computer Vision (Structure from Motion and Image-Based Modeling); we use Pyhon Photogrammetry Toolbox to elaborate 350 pictures (Nikon D5000) divided in 12 groups (external walls, tower-inside, tower-outside, palace walls, fireplace, ...).

The different point clouds were rectified thanks to some ground control point. Using a Trimble 5700 GPS the GCPs were connected to the Universal Transverse Mercator coordinate system. The rectification process was lead by GRASS GIS using the Ply Importer Add-on.

To avoid some problems encountered using universal coordinate system in mesh editing software, we preferred, in this first step, to work just with only three numbers before the dot.

2) The aerial photography campaign 

After walls documentation we started a new campaign to acquire the data needed for modeling the surface of the hill (DEM) where the ruins lie. The best solution to take zenithal pictures was to pilot an electric drone equipped whit a video platform. Thank to Walter Gilli, an expert pilot and builder of aerial vehicles, we had the possibility to use two DIY drones (an hexacopter and a xcopter) mounting Naza DJI technology (Naza-M V2 control platform).

Both the drones had a video platform. The hexacopter mount a Sony Nex-7; the xcopter a GoPro HD Hero3. The table below shows the differences between the two cameras.

As you can see the Sony Nex-7 was the best choice: it has a big sensor size, an high image resolution and a perfect focal lenght (16mm digital = 24 mm compare to a 35mm film). The unique disadvantage is the greater weight and dimension than the GoPro, that's why we mounted the Sony on an hexacopter (more propellers = more lifting capability). The main problem of the GoPro is the ultra-wide-angle of the lens that distorts the reality in the border of the pictures.
The flight plan (image below) allowed to take zenithal pictures of the entire surface of the hill (one day of field-work).

The best 48 images were processed by Python Photogrammetry Toolbox (one day of computer-work). The image below shows the camera position in the upper part, the point cloud, the mesh and the texture in the lower part.

At first the point cloud of the hill was rectified to the same local coordinate system of the walls' point cloud. The gaps of the zenithal view were filled by the point clouds realized on the ground (image below).

After the data acquisition and data elaboration phases, we sent the final 3D model to Cicero Moraes to start the virtual reconstruction phase.


3) The Orthophoto

The orthophoto was realized using the texture of the SFM's 3D model. We exported out from MeshLab an high quality orthogonal image of the top view which we just rectified using the Georeferencer plugin of QuantumGIS.
As experiment we tried also to rectified an original picture using the same method and the same GCPs. The image below shows the difference between the two images. As you can see the orthophoto matches very well with the data of the GPS (red lines and red crosses), while the original picture has some discrepancies in the left part (the area most far away from the drone position, which was zenithal on the tower's ruin).

4) The DEM

The DEM was realized importing (and rectifying) the point cloud of the hill inside GRASS 7.0svn using the Ply Importer Add-on. The text file containing the transformation's info was built using the relatives coordinates extracted from Cloud Compare (Point list picking tool) and the UTM coordinates of the GPS' GCPs.

After data importing, we use the v.surf.rst command (Regularized spline tension) to transform the point cloud into a surface (DEM). The images below show the final result in 2D and 3D visualization.

Finally we imported the orthophoto into GRASS.

That's all.