Tag Archives: SFM

Fun with SFM – part II: The results

So, hello, dear all, I am back from a very busy family weekend – and I would like to entertain you now with our second part to our SFM-tutorial!

Due to my work at University, I have the opportunity to work with Agisoft Photoscan, which is quite the same as Agisoft Metashape. You can find all the information on this software here – I am very used to it, it is very easy to work with, very easy to understand and you hae all the features collected in one software. Of course, there are other softwares, even a lot of freeware for 3D modelling – I used to work with them as well and I think, the next step will be a comparison of the different softwares by modelling the same object. I am just looking for the time to do it, because: My dissertation has to be (okay, should be) finished by December… so, time is really rare in my life right now…

But this post is all about my little Eros/Amor riding his hippocampus. You can find the information on this example here in my first post.

I opened Agisoft Photoscan and loaded all the images I wanted to use meaning all the pictures I have taken. The first step is the aligning of the images. The software searches for the same points on different photos and matches them.

Step 1: Aligning the photos
Step 2: Building the point cloud

The next step will be the point cloud – of all the points that the software could match on different photos (the best thing is that you get the same point at least out of three different directions) there will be a so-called point cloud as a result. As you can see in the second pic here, there are a lot of “noises” around my object – you can barely recognize Amor’s foot an the tail of the hippocampus.  So, the next step is to clean this mess up. You just mark all the noises around your object and delete it. Another possibility is to mask your photos before aligning them and starting to build a point cloud. Either step will take its time.

In my first post I mentioned the different directions you have to take the pictures from. Here is a screenshot of all the thumbnails of my pics, just to help you geting an idea.
And again, the front view of my model, here already “meshed”.

So, after cleaning you will get a very nice point cloud showing just your object. I just took the side view of this sarcophagus, so my object remains quite flat with no other sides.

After the last step – the finished model!
In detail and without texture the model consists of a grid that connects all the points with each other and gives the actual shape of the surface.

After building the so-called dense point cloud (you may notice the features of the relief getting clearer), we can start with the last step – to build the actual model. As you can see here, I really tried quite hard with the texture as well. The texture can be build out of all the coloring information you have in your pics. This step is not necessary, if you are just interested in the shape of the surface. Therefore, you will get better results without coloring your model, because your eyes might get betrayed by all the shades and colors.

If you want something nice to show your students or your friends, then go for the texture. 😉

Of course there are further things to do on Agisoft Photoscan/Metashape or with other software – it’s a playground, so feel free to try. And remember, I took these images with my phone camera, so no pressure on that. Of course, your first tries may suck, but hey, it’s a process. I am still learning too and I am still discovering new fascinating features and possibilities.

I hope you enjoyed this little post – stay tuned, keep calm and start 3D modelling. 🙂

All the best,

Astrid

Saxa Loquuntur – How to understand the tales of stones

As I told you last week, I was on my way to Italy – and now, I am back here in Austria, sitting in my appartment, enjoyed a wunderful silent and easy Sunday without people and with a lot of reading and a lot of movies. And no, I did not think about my thesis. 😉

I was in desperate need of such a day – and I have taken off the next two days, just to recover myself, get my appartment cleaned, my clothes washed and my brain restarted. What helps you better with that than housework? At least, it helps me a lot. 🙂

So, here I am ( I admit it, the photo is from 2016), but still, it was another summer course and I am busy taking measurements of the letters of an inscritpions – while my colleague, who should acutally write the measurements down ( we were working in pairs), took this photo. 🙂

This post will be a short summar of my trip to Italy. One of many trips to the lovely city of Aquileia, now not that big deal, but maybe some of you know Grado? On your way to Grado you are passing Aquileia. If you have time, take a stop, get some ice cream and wander around. The city has some secrets to share.

I was here for the epigraphic summerschool of our university – this time with a little presentation of myself and some really important tasks, e.g. doing photographs of unpublished inscriptions and showing some photogrammetry and SFM, to get people involved with the material.

For me, teaching like that (yes, I may look like the holiday version of Lara Croft, but actually this is my teaching outfit on summer courses near the sea) has one important feature to give to students. Epigraphy is about text, yes. That does the name of this discipline define very clearly. Something engraved on a material. But for the text you need the material. And therefore, it is not only important to note the text, to follow the rules of documentation, translation and editing of inscriptions, but also to actually feel it. You have to work on the stone, the metal plate, the potsherd, etc. You have to touch it, describe it, think about it. You take measurements, descriptions of the reliefs and the decoration, you note everything you came across on the setting of the inscriptions and the letters.

How do we do an epigraphic course? Well, we start with one day of introductional presentations and then we will go and work on the material – that is, why Aquileia is so great as location for epigraphic courses. There is a very large number of inscribed stones – so, one will never get lonely. I can tell by now, it was my fifth course and I am still finding new things in the museums… 😉

Inscriptions are by means hust found in museums – some of them exist on mountainious passes, like this example here, dating back to Roman times and prooving this site as an ancient trade route.

So, how to read an inscription? Well, first step: No. You just don’t go there and start reading. Latin epigraphy (which we are dealing with in this post) is characterized by certain abbreviations of names, titles, positions of military and civil Roman careers, as well as by certain formulas. Things change by time, so some of these characteristics are even important for dating the whole thing. So, before you actually read the inscription – you spell it. You sit, you have your pen and your sheets ready and then you start to decipher one letter after another.

After spelling comes the reading and the resolving of the abbreviations. So, this will be step 2. Then you describe everything on the inscription field, the letters and so on. Next, the monument itself has to be described. What is it, when has it been found, where has it been found, are there any other notes on this site, other insriptions or dated material? Where is the object located now, does it have an inventory number, etc. Describing is hard work, you know. I am sometimes just taking the pictures, my colleagues describe the objects and help me with the setting of the lights. It is not that easy to take good photographs of inscriptions – basically, you should be able to read the whole text. So, this will be a question for the right light. In photography, everything is about light.

As far as I am now, I am unfortunately not allowed to post any photographs showing me with my working methods on the objects (how I set the light etc.), but I am working on it – I think it will be a nice tutorial for those of you interested in the process.

For the understanding of the many tales our material has to tell us, especially when bearing inscriptions of any kind, please, make yourself clear that you are dealing with a source which carries the directly engraved thoughts of people now long gone and vanished from this world of ours. This is why epigraphy is actually a very important discipline – yes, as long as they do not forget about the importance of involving archaeological method and information as working.

I hope, I have given you a short insight of our summercourses – there will be one next year, same time, so… if you are interested, please, do not hesitate to ask me about it.

For now, I hope you enjoyed this post – please, feel free to ask any questions on your mind. And stay tuned for more stone-things. 🙂

All the best,

Astrid

The “D”- and the “H”-part

It was a post of my dear LaTeX ninja, talking about the pros and cons (okay, basically the pros) of one getting started doing Digital Humanities (you can find the original post here). I just flipped through it, until the following sentences:

Because the whole point of DH is that you’re not either a programmer XOR a Humanities scholar. It’s the combination of both. Most people see that combination as some sort of 30/70 or 40/60 kind of thing. I think it has to be 100/100. And yes, that means you’ll have to be a freak with a 200% workload. I’m pretty alone with this opinion, however, so don’t panic. Most people don’t see it like that at all.  I’m generally a bit of an eccentric and maybe some might perceive my opinion to be extreme. Well, sorry, but I like extreme. I think that “real DH” should mean 200%, or even better: 300%. 150% programmer and 150% Humanities. Be hardcore at both. At least that’s my personal goal.

So, I learnt that she is somehow extreme and liking it, what I actually always thought about her, and I learnt that 100/100 is a quite ambitious goal. And then I started thinking about myself and my abilities in DH. I splitted it up, there is an “D”-part and an “H”-part. So, I would like to start with my “H”-part, meaning the humanities, basically Archaeology and Classics. I am archaeologist by training, as well as ancient historian. I sometimes like my description of myself as an archaeologist with “special features”. You know, coming from a field dealing with images, but also able to read ancient sources (well, of course, all my colleagues are able to read, but I discovered that many historians and philologists keep thinking that an archaeologist just does not use written sources –  or at least, in the wrong way).

But my special features are not just my “reading skills” all alone. I did some courses in linguistics and in geomatic engineering as well, some workshops on digital methods in the humanities, …

So, if the “H”-part, meaning my archaeology-me by training, is 100%, because I have a degree and doing my PhD, then how does my “D”-part look like?

My first tries with SFM – I worked with freeware and was amazed by the quality. Here you can see a relief side of a sarkophagus with some holes, because my photos were not that good.

I told Sarah that my “D” part is about 24.6%. The workshop on Digital and Practical Epigraphy in London (click here to read the whole post) increased my knowledge about 4.2% (don’t get me wrong, it was a 100% success, but a 100% in my “D”-part are standing for a degree, so I had to convert it). So, we are located at 28.8% by now. The moment I can run my first Python scripts in a way the are meant to run and work out, I think, my rating will increase up to 36.9%. 🙂 Cheers to that, I think.  I am convinced that this is a great number, for the sum of 3 and 6 is 9… Isn’t that beautiful? Okay, enough with the maths.

Then I thought about which part is more important to me. Basically, this is like the question, if I like bones or late antique Church Fathers the most. I cannot decide, so it is quite unfair. I need both parts, never mind how much percent they have. I am convinced that my archaeology-part is sometimes at 120%, 20% are just crazy happiness, e.g. because I am allowed to take photos in a museum on monday (so, when all museums are normally closed and it is just me and the artefacts). Sometimes ist about 84,7%, because I am that exhausted after a very concentrated climbing session or my fitness workout. My “D”-part is like a static shadow behind my the “H”-part, smiling on the archaeology-me playing with bones or being fascinated by stones. The “D”-part does perfectly know that its whole existence is mainly about my archaeology-me letting it be. So maybe the “H”-part is first place in a hierachical structure. The “D”-part comes second and is caused by the “H”-part. Does sound like some kind of splitted personality, am I right? (Just a reminder: Yes, we are all crazy here, trust the Hatter, I tell you that).

My photos are better, my knowledge of the software has increased. But still, there are a lot of “mysteries” for a happy noob like me. And I like mysteries. 🙂

So, if I had never ever found the idea of being able to do SFM and 3D-stuff fascinating, if I had never ever the interest in photography, I would never ever have ended up this way. I am a trained archaeologist, capable of mastering the “H”, and a proud and happy noob, dealing with and experiencing the “D”, while learning on the job. I think, this is a very good mixture.

What about you? What is your “D” to “H” ratio? How are you working on yourself and your skills?

All the best,

Astrid (currently 28.8%/105% – because I could post some of my screenshots of my SFM-journey…) 🙂