Section 6.2 - Titolo - From Physical Cultural Heritage to Digital one - Part 2 (min. 18:31)

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En provenance du cours de Sapienza University of Rome

Recovering the Humankind's Past and Saving the Universal Heritage

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Sapienza University of Rome

Recovering the Humankind's Past and Saving the Universal Heritage

128 notes

Archaeology is, among human sciences, the discipline with the strongest importance for the rediscovery, but also for the preservation and protection of cultural heritage, as Humankind’s universal patrimony. You will be introduced to the way we ourselves reflect on and are engaged with the study of human past: from the practical and material recovery of ancient traces in the field to the study and interpretation. On the other hand, the discovery of human past implies the correct conservation and presentation for both experts and general public: the study and protection of the past we share every day prevent from any possible destruction, misuse, abuse and thus cancellation of human memory. “Recovering the Humankind's Past and Saving the Universal Heritage” presents to a large public Archaeology as a historical discipline: through an inter-disciplinary perspective you will follow the evolution and change of archaeology to the moment when natural sciences contributed to make the historical reconstructions scientifically sound; the aid of informatics and of virtual reconstructions gives new fascination to the already strong suggestion of Archaeology, as the discipline of discovery par excellence. Within this frame, Ebla, which is the glory of the Sapienza school of Oriental archaeology, will have an exemplary meaning in the course development as a long lasting experience on the field and an excellent example of the scientific results of combined researches and disciplines. Moreover, the course will focus on actual, innovative instruments to preserve, monitor and give value to cultural heritage through a multidisciplinary approach, based on a deep archaeological and historical knowledge but also on ICT technologies. The wide adoption of ICT technologies in our daily life is also impacting in the way in which we interact with our cultural heritage in particular in terms of preservation and dissemination of cultural objects. In this course you will learn the basic techniques to digitize cultural objects and obtain 3D digital copies of a physical objects such as statues, vases or archaeological sites. We will also discuss how to structure the raw data in order to facilitate and make effective the access to digital contents. In particular, we will present the European Data Model, a framework for collecting, connecting and enriching data on cultural objects provided by a number of museum, archives, sites and libraries in Europe.

À partir de la leçon

Week 6 - Digitizing Cultural Objects and 3D virtual reconstruction

In this module, Emanuel Demetrescu will explain us the last methodologies and techniques in the field of 3D acquisition and reconstruction of cultural heriatage. These applications improve the knowledge and preservation and have a central role in the way we can communicate cultural heritage to the society. Making digital copies from real objects now has several very fun and precise technologies that are also available to everybody at very low cost budget. Demetrescu will show us how to use these tools to make our own models and share them with others. The virtual reconstruction of no-more-exstant objects (like a lost temple) will be the argument of the last part of the module: a state of the art of the methodologies will help us to understand how to approach such a process from a scientific point of view (archaeological method). Homework available since 1 Jan.: Quiz week 6

Section 6.1 - Titolo - From Physical Cultural Heritage to Digital one - Part 1 (min. 17:28)17:28

Section 6.2 - Titolo - From Physical Cultural Heritage to Digital one - Part 2 (min. 18:31)18:31

EXTRA: Tutorial Section 6.2.2 - make your copy of Visual SFM (min. 3:43)3:43

Section 6.3 - Titolo - From Physical Cultural Heritage to Digital one - Part 3 (min. 17:33)17:32

Rencontrer les enseignants

Paolo Matthiae
Emeritus Professor of Archaeology
Dipartimento delle Scienze dell'Antichità
Davide Nadali
PhD in Near Eastern Archaeology
Andrea Vitaletti
Ph.D. in Computer Science
Computer Science
Emanuel Demetrescu
PhD candidate

Hi, in this lesson, we will be talking about the 3D

reconstruction of real objects, starting from photos in practice.

The previous lesson was about the theory and

methods of 3D survey in cultural heritage.

In the current, in the current lesson, sorry, the 3D survey in practice

using an image-based approach, how does it work?

We will take some photos on, on the field.

We use some software tools.

We obtain a point cloud, and we use it to make our final 3D model.

Okay, let's see how in practice here.

[NOISE]

Okay, I take my

old iPhone 4,

and, let's start,

our 3D survey of,

the statue [SOUND] Okay.

A set of photos useful for our 3D reconstruction.

This is a, a very interesting statue.

It is from the Cucuteni culture, nowadays in Romania in Europe,

estern Europe and is a, a reproduction, a clay reproduction of

a statue from the fourth millennium, before Christ.

Okay, now let's start to make our 3D model.

The first software we will use is the VisualSFM.

That is, stands for structure for motion.

The Visual Structure for Motion is a free for personal, non-profit or

academic use, and it's perfect for our purpose of this course.

You can download it for every OS, but

I warmly recommend Windows version because it's easier to be installed.

But it's fine also for Linux, Mac OS X, and so on so forth.

First of all, we open our VisualSFM folder,

and start the VisualSFM.exe file.

Here we get this kind of visualization, the VisualSFM is a software with a blank window,

and we can import our data set, our files, the photos just took with the iPhone 4.

So, we have to follow, to open this way

open more from the file selection.

Menu and, or through this icon.

In the GUI

go to the folder and we select all the files present.

Now the, the VisualSFM software is charging the images inside the canvas.

Okay, well the photos are now inside VisualSFM.

First of all,

we have to compute the missing matches between these photos with this icons.

With this tool, VisualSFM finds for

homologous points between two or more photos I mean.

Between this and this photo, there are similarities.

The same points on the these two photos, for examples, the eyes of

the statue that are the same in one photo and the second photo.

With this command, we get some extra

files in our dataset and for each JPEG photos,

we obtain a .sift file, I mean, with the, in this sift file,

there, are written all the other photos similar to the current one.

So, this is the photo and in this file we have all the other photos that,

that there are similar to this one.

Okay.

The miss,

miss, the missing matching point finished, in some minutes.

Okay, and now we have the computed 3D reconstruction with this

icon here, and what is going on?

VisualSFM is reading all the information about the.

the similarities between the photos and is drawing on the 3D scene.

The relative position of these photos in the space and

it computes the so-called sparse points.

Here we have the representation in 3D

of the homologous points between the photos of the dataset.

So it is not a very accurate point cloud.

It is just a starting point for..

..to have later the dense point cloud, the accurate one.

[NOISE]

Okay, now summing up of this first part.

The steps involved, the Sift process,

we use all the photos in the, we take all the photos in the VisualSFM and

we look for homologous points between photos.

So, there are an unordered series of photos,

and we, and the software find out the homologous points between these photos.

This photo and this photo are one next the other one, and so on, and the bundle

the extraction of, of the position, the relative position of the cameras.

In the scene and in the end the creation of the dense point cloud.

Okay. In this course we use VisualSFM but

there are other software we can use.

There are free open source software or pay software,

there is Apero-MicMac that is a that has a photogrammetric approach very accurate.

And you can use it freely also for

commercial projects and there is also the Python Photogrammetry Toolbox.

The same license, or there is a, a paid software like the Agisoft photo scanner.

It works very well, or instead of scan and so on and so forth.

Okay.

Now, the second software we will use Meshlab.

It's open source, and it's, so it's free to use also for commercial.

Is developed by CNR-ISTI Pisa, Italy and

is very common software, is used worldwide.

With this software you can edit and make 3D content from real objects,

and, with great level of accuracy with the state

of the art algorithms in 3D computer graphic. You can download it for

every OS, Linux, Windows, and MacOS and so on.

Now we have the dense point cloud and we need to open it with the MeshLab software.

We search it on, on Google and the first one result is MeshLab,

and here we can load it for Windows, for Mac OS X and for Linux you have..

..in the repository of your distro.

Here we download the exe, the Mesh Lab is free, so

we have no problem and in seconds we get a free copy.

Now we have opened, now we opened the Mesh Lab too and we,

we open project file the VisualSFM reconstruction is a project for

Mesh Lab where we can import the sparse point cloud.

So the not very accurate point cloud.

with all the homologous points

we turn off the light from here and

we can zoom in with the middle mouse button scroll to see.

the statue

Okay, now we open the layer button here.

To see to have a look a the content of this project we have one point cloud,

and here several photos connected to this point cloud.

They are the photos I just took, with my iPhone.

Now we have to import, the dense point cloud.

We can import the dense point cloud from the file menu,

import mesh, and we can find.

Our point cloud just inside the Cucuteni folder

cucuteni statue .ply this is the format used.

Okay.

So now we have two different.

Point clouds.

One dense and one sparse.

We need to work on the dense one.

So we have to uncheck the eye of the spare one and work just on the dense one.

First of all we have a lot of stuff that we don't need.

So all the street, outside where I took the photos for you.

For the exercise.

It's better outside for the light, and for the characterization of the photos.

We have a lot of feature in the photos.

There are stones of the streets the walls of the street and so

on, and the photogrammetry works better with a lot of objects inside the scene,

and we have to clean this point cloud.

through trashing all the point we don't need at all.

So, we have some tools inside Mesh lab.

Here is the selection, window selection, and here we have the,

point delete.

These two commands.

[SOUND] We have no we have only a dense point cloud

of our statue but we need a surface of our statue.

Something to to print or to paint over the color.

So we select the filter menu and remeshing simplification and reconstruction.

We, we select the surface reconstruction with the algorithm named Poisson

so with this tool, we can obtain the surface of the statue

starting from this dense point cloud.

The parameters you can use are twelve and ten for the octree depth

how much resolution we have to set in this 3D statue Okay.

We apply this and calculate.

And here's what you get.

A mesh, a poisson mesh, obtained from the

dense point cloud.

This is a blank mesh so we need some color.

And we have several photos of this statue and we can start from them to obtain

the color of the, the model and from the filter menu.

The texture menu we can obtain the parametrization plus texturing from registered raster

The registered rasters are the photos.

So we set a big texture of 4,096.

a texture name will be texture.png

And we check this, all these fields, color correction, and so on.

And we apply to obtain our color from photos.

Okay.

And now we obtain our 3D model of the statue.

We can, improve this model with other steps of refinement,

in other 3D software like Blender 3D.

Or just inside the Meshlab.

But for the sake of simplicity.

You will find out that these are just on the complete video

you can access on the course website on in our course.

Have a look to the export of this this statue.

We can export it in the OBJ format from the file menu export mesh OBJ format and

choose setting options, we have to, set the text coordinate and,

to be sure that there is the texture dot png, file.

And that's all.

Summing up this part of lesson.

The steps involved in mesh lab are cleaning the dense point cloud.

Creating the mesh with the poisson filter.

And creating the textures from the photos.

And the export of this model to the 3rd and last software.

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