Marco di Ioia, architect and fellowship researcher at the Institute of Technologies Applied to Cultural Heritage – Virtual Heritage Lab in Rome, is sharing a wide overview of new technologies utilized in the archaeological and historical research.
His main expertise is represented by architectural 3d modeling, texturing, computer vision based 3d modeling, CAD 2d-3d modeling, Laser scanner data optimization, video editing, character modeling, virtual crowd animation and much more.
Advantages of the new digital technologies applied to archeology
By Marco di Ioia
New technologies have opened, for the cultural heritage, new infinite possibilities, which only a few years ago could not even be imagined. The impact of digital technologies for cultural heritage affects both access for users and opportunities for professionals.
The new portable devices, just to have an example, like tablets and smartphones, are nowadays equipped with integrated GPS, quad-core processors and very powerful video cards, and, for the first time ever, they permit to attach virtual reconstructions to the archaeological sites. Thanks to the augmented reality, the visitor is therefore able to enjoy a wide amount of site-related content, exactly on site and on time.
It is actually an electronic tour guide, always ready to use and customizable, which can be enriched and implemented with videos, e-books (very recently we had the release by Apple of the editor for this type of content, which is specifically dedicated to the schools and education sector) or serious games 3d.
On the side of archeological surveys, the technological innovations made great strides, in terms of accuracy and adherence to acquired data, and also for simplicity in use and speed.
Therefore, compared to the digital tools which were available just a few years ago, nowadays technologies permit to speed up the work during the mapping as well as during data processing, no matter the size of the investigated object – starting from the relief / reconstruction of the landscape, through the architectural structures, to end up with very very small artifacts.
For the reconstruction of very large territories, the ideal would be to use satellite remote sensing. It is indeed a very high level technology, you can get extremely precise results (below the meter accuracy) even if it needs adequate funds. Also it is possible to carry out aerial surveys with dedicated flights, and then get data from the three-dimensional stereo pairs.
Alternatively, with a smaller budget it is possible to implement a very trendy solution: sending in altitude a “drone”, which is a kind of no-pilot, radio-control helicopter equipped with electric motors and lithium batteries (although, unfortunately, with a short duration), as well as an overhead digital camera with remote control, to make a photographic survey. The best models are also equipped with GPS, so, if you do not trust too much your talents as a pilot of airplanes, you can plan in advance the path of the photo campaign, and then just take off. The rest relies on the automatic pilot.
Those, who are completely strange of flying aircraft models, have also the possibility to connect the remote control of the drone to the personal computer, and make endless practice at home with drone virtual flight simulator: the software is perfectly matching to the real model’s effective response, thus avoiding the risk of destroying all the expensive equipment at first attempt. It is amazing to think that only up to 4-5 years ago, for the same type of work, we relied on air balloons and even kites (Kite Aerial Photograph)!
Another solution for high precision measurements is the use of so-called time-of-flight 3D laser scanner: it emits a pulse of light and calculates the amount of time before the light reflected by the surface of the object is seen by a detector: repeating this operation hundreds of times per second, it returns a three-dimensional cloud of points.
The 3d georeferenced point clouds are taken from various locations, until covering the entire surface of the investigated site. Many stations are required, as eventual obstacles create shadows, corresponding to missed data; therefore the same area has to be scanned from another station that is positioned in a different location in order to avoid the obstacle.
Then, all the stations are roto-translated in order to obtain a single cloud, and after that it is created a “mesh”: a three-dimensional surface composed of triangles, that joins all the cloud points, to be further properly optimized and textured for the final result.
Today, laser scanners can be settled even on moving vehicles as aircraft, helicopters, boats (such as in the case of a seabed survey for the underwater excavation of an ancient Roman ship) but also on “simple” cars. Accelerometers and gyroscopes constantly measure the acceleration and the angular velocity of the vehicle, then the software in post-processing is able to “clean up” the collected data, eliminating the noise (that is for example, the position inaccuracies due to the rough ground, or to wind turbulences in high altitude or sea waves).
If you do not have big budgets, or even with zero costs, you can be happy to use the many free online data, and through the use of GIS data managing software – even for example the open source “GRASS” – you can get a Digital Elevation Model (DEM) for most of the surface of our planet, with good resolutions up to 5 meters.
Regarding the relief of archaeological objects, if they are small (large more or less like a shoe box, for instance), laser scanners can be purchased with the same cost of a good laser printer, about $ 2,000, and achieve models of good quality, well-done and already textured.
These digital models can then be copied in the proper scale and number of copies by 3D printers, which using the reverse engineering process, can reproduce the original object in a resin copy. The technological processes of these devices are quite heterogeneous, depending on the type of printer, but the result (the resin copy) can be indeed very faithful to the original and surely more resistant and durable.
There are many and surprising innovations about economy and efficiency: nowadays with a simple photographic survey is in fact possible to achieve a beautifully textured 3d models. Indeed a great innovation in the field of archaeological excavation relief comes from the so-called “computer vision”. With the use of this technique in fact, starting from the photographic survey done with a good digital camera and taking into account some precautions regarding the number and position of the shots, it is possible to obtain a complete 3D model of the object.
The margin of error can vary from a few centimeters to a few millimeters, depending on the quality of the shots. Most of the software that manage such processes launch the calculation in cloud computing – in other words the shootings are sent to a remote server and then, after a few minutes of post-processing by very powerful computers, you receive a model preview. Then you have to cut away the unwanted parts, and re-launch the calculation; in the end you obtain an already textured 3D model. The results are really amazing in terms of communication quality.
In conclusion, looking ahead, the problem will not be any more about obtaining 3d models, and having technical expertise in modeling, since within a few years making 3D models will be like making photocopies. The central issue will rather be what to do with such great amount of data, I mean once the relief – in the form of scientific millimetric data – will be safe from structural collapse, and available for institutions and scholars.
The real challenge will actually be to find the best form of dissemination of data, in order to make them open and understandable to everybody, together with flora and fauna aspects and mostly anthropological aspects, which are absolutely necessary information to understand the ancient civilizations whose those objects – observed in the museum’s showcases as well as in the screen of a tablet – were direct witnesses.
Original article (Italian language) PDF