Thursday, 24 April 2014

The Andean child and the Happy mummy's Day! 3

Steps of facial reconstruction
She was so tiny and fragile that I feared catch her in my arms. She was wrapped in a blanket of plastic bubble and  filled with silica so she did not suffer the effects of moisture, she was in a corner of the Rosicrucian Egyptian Museum and surrounded by care and discretion on the part of the curators.

Dr. Moacir Elias Santos (archaeologist) holding the child and the curator Ms. Vivian Tedardi
 I met her in May 2013 when I participated in an event at the museum. On occasion I could not give much attention to the child, because at that time the star was Tothmea mummy. We were presenting the Egyptian mummy to the general public and the press. Even so, the Andean child entered the meeting topics and we was more or less agreed that the museum would mobilize for a CT scan in that little body girded with a lot of mystery and historical importance.
 
Poster of the conference in Portuguese

 Months later I learned that a group of IFPR (Federal Institute of Paraná) linked to the course of Radiology, was developing a job with the Andean mummy. Quickly I contacted the professor Marinei Pacheco and her student Priscilla Lopes. They accompanied tomography whole body of the child and they were working on the data so that they could with this, among other things, get to her age when she died.

Reconstructed body from CT-Scan, InVesalius software
I was in Sao Paulo when I received the files of CT-Scan. I had a thousand things to do but I had to forget them for a while because I was blown away by what I saw. Sitting on the desk of the hotel I rebuilt the tomography for 3D. Initially it appeared the body of a very young child. By regulating the amount of transparency, the bones revealed them. I could even see the tiny spheres of silica. Something caught my attention that surrounded the tiny little arm of the mummy, a small bracelet that I did not notice at first.
 
Banner (in Portuguese) made by the group of Radiology of IFPR

She was in an almost fetal position, hiding the face with the legs folded. Involuntarily I began to imagine how would have been the days of that child while she lived. What would have taken her to lose her life? How did your parents dealt with that? Where she lived in the Andes? The questions are many, but the answers... very few.

Only the bones imported in Blender 3D software
 So I returned to my town (2100 Km away), I began to reconstruct the face. Gradually appeared the face of a beautiful little girl, with slightly pronounced teeth. I decided to configure a sweet smile on that face, to immortalize a moment of joy during her brief life.

Soft tissue drawn from the depth markers
 The small Andean died long ago, I stay sad to see skeletons of children, but from this dismal history new friendships emerged. When Priscilla finished the work related to radiology, she posted on Facebook a photo with the scientific panel describing the process. In thanks she quoted a phrase taken from the post where I have explained the reconstruction of another child, actually a baby ... the baby mummy of St. Louis. I was extremely honored to happy at that time. The kids are gone, those who are here cooperating and facial reconstructions will gather in an ehxibition about childhood in antiquity. The small Andean mummy, after hundreds of years will have many little friends at her side.


 Returning to talk about Happy mummy's Day! few days ago I received the airline tickets by email and I quickly began to separate the images to compose the slides that will be presented at the roundtable where we discuss the project (about the Andean child). After so long working with this I still get inspired and eager for the day to come soon and I can show viewers the steps of modeling. More than making me anxious to present, I stay also in relation to what the other members will show. It will be the first time I will participate in an event where all the researchers who developed the process will speak on your part making up a complete picture of how things been made.

Preview render in one of the last steps of works
 This mix of viewpoints and different performances will surely drive this serie of experience to a new and exciting project where science will be the biggest benefited.

The presentation will happen at 17th of May and if you, dear reader, know someone in Curitiba-PR (Brazil), please, inform that person about the conference, besides being interesting the entrance is free.

Adress: Auditório da Ordem Rosacruz, AMORC (Rua Nicarágua, 2620 – Bacacheri).
Tel.: +55 41 3351-3024 or by the email: cultural@amorc.org.br

More informations (in Portuguese): http://www.amorc.org.br/noticia–16.html


A big hug and I see you in the next post! 

Tuesday, 22 April 2014

Arc-Team tries Large Scale Reflectance Transformation Imaging (RTI)


With the data, collected during our mission presented recently in the post „@MAP“the Arc-Team Mobile Mapping Platform, we've tried for the first time to apply a method called Reflectance Transformation Imaging (RTI) on landscape:

Aerial Photo of the project area taken from Arc-Teams Drone

RTI is a computational photographic method that captures a subject’s surface shape and color and enables the interactive re-lighting of the subject from any direction. RTI also permits the mathematical enhancement of the subject’s surface shape and color attributes. The enhancement functions of RTI reveal surface information that is not disclosed under direct empirical examination of the physical object. (...) RTI images are created from information derived from multiple digital photographs of a subject shot from a stationary camera position. In each photograph, light is projected from a different known, or knowable, direction. This process produces a series of images of the same subject with varying highlights and shadows. Lighting information from the images is mathematically synthesized to generate a mathematical model of the surface, enabling a user to re-light the RTI image interactively and examine its surface on a screen.“ (http://culturalheritageimaging.org/Technologies/RTI/)

We've used the processing software and viewer of Cultural Heritage Imaging, their RTIBuilder software is made available under the Gnu General Public License ver. 3.


RTI is usually used for objects of small or medium size beause of the difficulty or impossibility to illuminate whole structures or even areas / landscapes.


At this point GIS comes to our aid:

Starting from a DTM it's easily possible to create shadow reliefs with GRASSGIS' module r.shaded.relief
The highlight of the module in our case is the capability to modify the altitude of the sun in degrees above the horizon and the azimuth of the sun in degrees to the east of north. 



In this way we could produce artificially the needed data for our RTI-landscape attempt. 
The next step was to export from GRASS a set of 60 images with different lighting positions creating an imaginary light dome around the object:


At this point we reached the first bottelneck of our approach:

Usually, you include at least one reflective sphere in each shot. 

The reflection of the light source on the spheres enables the processing software to calculate the light direction for that image. 

So we had to create and copy in every image a fake sphere with the reflection corresponding to the sunlight direction choosen in GRASS.

It was a stiff piece of work!

At the end everything was ready for processing the images in RTIBuilder. The single steps in the software are very easy to execute and well described on the ProcessingGuide

We've just had some problems with the size of our images (8200x6500 pixels), which the software couldn't process, but maybe it was because of the age of our hardware...

After reducing the image-size everthing worked fine...



At the end, after installing also RTIViewer, we've held in our hands an interactive scene of an archaeological site of nearly 10.000m2 which is almost invisible from the ground.


Monday, 21 April 2014

„@MAP“ the Arc-Team Mobile Mapping Platform


In Summer 2013 Arc-Team was charged with the task to survey a micro-DTM on an archaeological area of about 10.000 m2.
The underlying archaeological remains on the side cause small differences in height on the surface and the shape of a nearly 60 x 60 meters large structure was known from aerial photographs.


We've had only 10 hours of fieldwork at our disposal and exploring our options we've made some numbers games:
  • Doing the job with total station would allow us to take an average of 5 points per minute, which means a (very optimistic) total amount of 3000 points in 10 hours. (2 operators)

  • Using our DGPS, the stroke per minute increases up to a maximum of 15 points per minute, working with continuous point capturing mode, having an operator on the field who's stepping forward, putting down the pole and balancing the bubble eyery 4 seconds. The total amount in this case is about 9000 points. This means an average of only 0,9 points / m2. That would be far to few...


So what would we going to do?

In this occasion we've had the idea to adapt a monocycle in order to have a rollable vehicle carrying the GPS antenna and maintaining a constant distance to the ground.
The result you can admire in the illustration below.



By the help of this tool we were able to increase the stroke on 42 points / minute and a total amount of almost 25.000 points. This means an average of at least 2,5 points / m2.




The result of our efforts was quite lovely: GRASS GIS produced a high quality DTM from which we derive 3D views, isolines and shaded reliefs.

The official name of the trolley is „@MAP“ Arc-Team Mobile Mapping Platform. ;-)

Sunday, 20 April 2014

Happy Easter

I write this fast post just to wish you a Happy Easter!
In these holidays I am testing very much ArcheOS 5, hoping that we will be able to release it soon (I'll do a new post connected with the first report I wrote in the mailing list). 
BTW, considering the occasion, I thought it was a good idea to check which of the many old easter eggs are still present in the next version of the system and here is what I found:


The traditional Mozilla easter eggs are still working. Try to type about:mozilla in the address bar and you can read some sentences from the Book of Mozilla.


Try out this command: apt-get moo

But my favorites are still these:

aptitude moo
aptitude -v moo
aptitude -vv moo
aptitude -vvv moo
aptitude -vvvv moo
aptitude -vvvvv moo
aptitude -vvvvvv moo

If you do not understand the joke, than maybe you have to read "The Little Prince" of Antoine de Saint-Exupéry.

That's all I found. The other easter eggs I knew (Star War in OpenOffice and the fish of Gnome) seems to missing in ArcheOS 5 (I guess due to the migration to LibreOffice and to Gnome 3). However, this post is nothing serious, so I hope you will forgive me if I do not investigate further about the matter :)... But before to leave, I want to let you a little easter present: in order to record some new videotutorial (they are on my long "good intentions" list), I reused the nice artwork Cicero Moraes did for ArcheOS Theodoric and created a wallpaper (this is optimize for my screen: 3823x2154 pixel, but you can download it and adapt it to your needs). I hope you like it :).



Again Happy Easter!

Saturday, 19 April 2014

ArcheoFOSS IX edition, deadline extended

Just a fast service communication,
for who is interested, the deadline of the 9th edition of the ArcheoFOSS has been extended till April 25. Here is the official report (from +piergiovanna grossi):

"IX Workshop Free / Libre and Open Source Software and Open Format in the archaeological research processes.
From survey to data sharing. Technologies , methodologies and languages ​​of open archeology. 

Verona , 19-20 June 2014 (IT)

To encourage the submission of proposals, the deadline has been extended till April 25. The organizing committee's aim is to support the broadest participation in the joint construction of a workshop of increasing quality, hoping that new proposals can be submitted by scholars, researchers, students, professionals, archaeological companies and associations, working in the field of Cultural Heritage and the FLOSS application.For proposal submission, please refer to the Call for proposals page.For more informations on the workshop, you can visit the page of ArcheoFOSS 2014."

The Arena of Verona (CC-BY-SA 3.0, author: Lo Scaligero)


Friday, 18 April 2014

How to take pictures for photomosaics in narrow conditions: A clever solution for a common archaeological fieldwork problem.


Everyone who works on archaeological excavations knows situations like this:


A narrow and deep trench or a wall near to the limit of the excavation area.

If subsequently we have to make a photomosaic of the profile or facade, it means:

  • either photographing from the top, hazarding the consequences like distorsion:

  • or splitting the photomosaik in numerous single tiles, and that means a lot of work!


A very simple and clever solution for this problem can be the use of a mirror:

Putting it down in an inclined position on the ground and positioning yourself on the opposite side (watch the illustration beneath and heed me kneeing outside of the trench), it allows you to take a shot of the reflection of your facade in the mirror.

Of course the picture will show the object mirror-inverted, but don't worry:
The rectification software will fix it again...


Thanks a lot to Granma for borrowing us her wonderful kitsch bedroom-mirror!

Sunday, 6 April 2014

Raw data to WKT: a point

Hi all,
I go on in recording basic videotutorial about FLOSS in archeology. This time I show how to turn raw data (from the total station) into WKT, starting with the simplest shape (a point). 
Like always I will upload this material on the DADP wiki, udpdating the old tutorial (I am using a preview version of ArcheOS Theodoric).

Here is the video, I hope it will be useful!





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