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.

The first photomosaic for architectural purposes?

In these days I am teaching various techniques to document in 2D cultural heritage with FLOSS (Free/Libre and Open Source Software) at the UNESCO master Open Techne. In particular I speak about photomapping and 2D photogrammetry technologies (to record horizontal and vertical surfaces).

Teaching students is always an interesting and instructive experience and , in most cases, it is often a mutual exchange of information, so it is more similar to a dialogue than to a monologue. I often learned a lot during these occasions and sometimes I have the opportunity to further investigate particular topics or to change my point of view on them, thanks to the discussion with other people.

Today it happened something like this: we were investigating the right way to correctly take pictures in order to use them for am architectural photomosaic (fortunately among the students there are not only archaeologists, but also architects, engineers, computer technicians, etc...), so I thought that a good example was the "photographic paint" maid in 1873 by Giacomo Rossetti, that I happened to see some years ago visiting the Musei Civici di Arte e Storia di Brescia (IT). You can see this "masterpiece" in the image below:

Photographic paint of S. Maria dei Miracoli in Brescia (G. Rossetti)

If I remember well what I read about this photographic paint, G. Rossetti built a wooden stage in order to collect the different photos that compose the photomosaic without excessive distortion. Of course now there are simpler ways to take good pictures (just read the last post Alessandro wrote about the UAV dornes we built), but the question of the students was: 

is this the first example of photomosaic for architecturale purposes?

To be honest, I was not able to answer the question. I just know that G. Rossetti presented its work during the exposition in Vienna in 1873 (where he won the medal of merit), but he started similar project earlier (around 1862). It seems that Rossetti's experiments were most appreciated abroad that at home (there is not even an Italian page in Wikipedia), so I think that better informations can be found in foreign countries.

 If some of the readers knows similar work of other photograpgers/artist (or of G. Rossetti), please report them on this blog, so next time maybe I will be able to better answer to student's question about this topic :).

Master UNESCO Open Téchne: Open Source technologies for Cultural Heritage

In 2013 will start the first UNESCO master "Open Techne" (Open Source technologies for Cultural Heritage). The master is organized by the Istituto di Formazione e Ricerca della Federazione Italiana Club e Centri UNESCO e il Centro di GeoTecnologie (CGT) dell’Università degli Studi di Siena, with the aim to train professionals capable of using innovative open source technologies in the investigation and exploitation of Cultural Heritage. The registrations to the master are open until December 15, 2012.
More info are available on the official webpage: http://www.istitutoficlu.org/open-archaeo/.

We (Arc-Team) will partecipate to the master, teaching the use of FLOSS in archaeology and focusing the attention on ArcheOS. It will be also a nice opportunity to work together with Luca Mandolesi (adArte) and Enzo Cocca (CGT), developers of pyArchInit, to try to better integrate their tool in a specific deb package (untill now we added pyArchInit into an experimental ArcheOS package together with CADtools and BobMax's VTP extensions for QGIS).