Hello from Slovenia

M.V.

Mu-43 Regular
Joined
Jan 16, 2017
Messages
39
Location
Slovenia, Europe
Real Name
Marko
Hi guys and gals,

I have just joined this forum, although I am a long-time m43 (and previously OM system) veteran. Besides being a photo-hobbyist and gear hoarder who dabbled briefly in 6x6 and 4x5 formats, I am also using photography in my profession, which is geoscience, more specifically structural geology.

I quickly realized the value of digital photography for fieldwork documentation - my first digital camera was Canon G3, from which I learned to appreciate portability, live view, great depth-of-field, and of course the fully articulated LCD display - all of these immensely practical in geological fieldwork. When the micro 43 system was announced I immediately knew this was it - finally an interchangeable lens system offering those same benefits, and promising compact and brilliant optics to top it all!

My kit from those early days (2010) and still used today comprises Lumix G2 camera, Panasonic 7-14 zoom, Panasonic 20/1.7 (mk1), and Leica 45 mm Macro (I never used the 14-15 kit lens that came with the camera). Those were the best lenses available at the time, I didn't care much for Olympus' offerings of the day. I still laugh every time I pack my small photo bag with this full kit, which is feather-light compared even to my old OM kit.

Admittedly, for my fieldwork I have later switched to the more practical and very good Sony RX-100 and finally to iPad Pro which allows me to annotate photos with geological data on the go (never mind the awful photo quality). In the recent years I have started using photogrammetry, which revolutionized field data acquisition in my work. You might not be all familiar with this, but basically it is a technique to create very precise 3D models of objects by using a large number of overlapping photographs taken from different viewpoints. If you are curious, you can examine my very disorganized collection of sample 3D models available here: Marko Vrabec on Sketchfab.

Sharpness of photos is very important for this (other image parameters not so much), so you can imagine this is again natural territory for m43 gear. I have several exciting projects in mind for which I will certainly need to update my existing gear, which is what brought me here... And I certainly hope to revive the hobby side of my photography, there's lots and lots of amazingly inspirational material in this forum.

Here is a small example of what I do and where - I climbed this mountain peak previous week to obtain photos of the area behind my back that my Master student is investigating. Using the Panasonic 45-200 mm zoom borrowed from my climbing buddy I shot some 400+ photos which we will use for photogrammetric reconstruction and interpreting geological structure. I should add it was bloody cold - the windchill factor was about -30 degrees C, and I have actually got frostbite on my toes plus the skin is currently going off my ears (but I guess all is ok as long as the ears don't start falling off as well :) )

Greetings from Slovenia, Marko


P1460438.jpg
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Joined
May 15, 2016
Messages
5,060
Location
Sydney, Australia
Hi guys and gals,

I have just joined this forum, although I am a long-time m43 (and previously OM system) veteran. Besides being a photo-hobbyist and gear hoarder who dabbled briefly in 6x6 and 4x5 formats, I am also using photography in my profession, which is geoscience, more specifically structural geology.

I quickly realized the value of digital photography for fieldwork documentation - my first digital camera was Canon G3, from which I learned to appreciate portability, live view, great depth-of-field, and of course the fully articulated LCD display - all of these immensely practical in geological fieldwork. When the micro 43 system was announced I immediately knew this was it - finally an interchangeable lens system offering those same benefits, and promising compact and brilliant optics to top it all!

My kit from those early days (2010) and still used today comprises Lumix G2 camera, Panasonic 7-14 zoom, Panasonic 20/1.7 (mk1), and Leica 45 mm Macro (I never used the 14-15 kit lens that came with the camera). Those were the best lenses available at the time, I didn't care much for Olympus' offerings of the day. I still laugh every time I pack my small photo bag with this full kit, which is feather-light compared even to my old OM kit.

Admittedly, for my fieldwork I have later switched to the more practical and very good Sony RX-100 and finally to iPad Pro which allows me to annotate photos with geological data on the go (never mind the awful photo quality). In the recent years I have started using photogrammetry, which revolutionized field data acquisition in my work. You might not be all familiar with this, but basically it is a technique to create very precise 3D models of objects by using a large number of overlapping photographs taken from different viewpoints. If you are curious, you can examine my very disorganized collection of sample 3D models available here: Marko Vrabec on Sketchfab.

Sharpness of photos is very important for this (other image parameters not so much), so you can imagine this is again natural territory for m43 gear. I have several exciting projects in mind for which I will certainly need to update my existing gear, which is what brought me here... And I certainly hope to revive the hobby side of my photography, there's lots and lots of amazingly inspirational material in this forum.

Here is a small example of what I do and where - I climbed this mountain peak previous week to obtain photos of the area behind my back that my Master student is investigating. Using the Panasonic 45-200 mm zoom borrowed from my climbing buddy I shot some 400+ photos which we will use for photogrammetric reconstruction and interpreting geological structure. I should add it was bloody cold - the windchill factor was about -30 degrees C, and I have actually got frostbite on my toes plus the skin is currently going off my ears (but I guess all is ok as long as the ears don't start falling off as well :) )

Greetings from Slovenia, Marko


View attachment 503745
Welcome to the forum.
Looks like you will be doing photography in fairly harsh environments, look forward to seeing some more of your photos
 

kevinparis

Cantankerous Scotsman
Joined
Feb 12, 2010
Messages
3,912
Location
Gent, Belgium
Welcome

would be very interested if you shared some of the techniques you use to generate 3D models from still images

cheers

K
 

kevinparis

Cantankerous Scotsman
Joined
Feb 12, 2010
Messages
3,912
Location
Gent, Belgium
It may well be that software, but the site ... from a quick scan tells me almost zero about how you do it

the OP obviously has done it.. their experience using the cameras we love would be a nice contribution to the forum

K
 

MichaelSewell

Mu-43 All-Pro
Joined
Sep 1, 2015
Messages
1,265
Location
Bootle, Cumbria, UK
Real Name
Michael A. Sewell
It may well be that software, but the site ... from a quick scan tells me almost zero about how you do it

the OP obviously has done it.. their experience using the cameras we love would be a nice contribution to the forum

K

TBH Kevin, the instructions from the site don't help a great deal either.
 

M.V.

Mu-43 Regular
Joined
Jan 16, 2017
Messages
39
Location
Slovenia, Europe
Real Name
Marko
Welcome to the forum.
Looks like you will be doing photography in fairly harsh environments, look forward to seeing some more of your photos

Thanks for the welcome.
Regarding harsh conditions, Slovenian Alps are quite benign most of the time, the past week being an exception because of the inflow of air from polar regions. In the past, way before m43 was invented, I made a couple of trips to the Arctic wilderness and was also doing a lot of caving photography, but nowadays the general lack of time and my beer belly prevent me repeating that!
 
Joined
May 15, 2016
Messages
5,060
Location
Sydney, Australia
Thanks for the welcome.
Regarding harsh conditions, Slovenian Alps are quite benign most of the time, the past week being an exception because of the inflow of air from polar regions. In the past, way before m43 was invented, I made a couple of trips to the Arctic wilderness and was also doing a lot of caving photography, but nowadays the general lack of time and my beer belly prevent me repeating that!
I used to do a lot of cave photography back in the film days as well, in places like PNG and NZ. Should buy a scanner some day to try and salvage some. I notice dye changes have ruined a lot of the colour images.
 

M.V.

Mu-43 Regular
Joined
Jan 16, 2017
Messages
39
Location
Slovenia, Europe
Real Name
Marko
Welcome

would be very interested if you shared some of the techniques you use to generate 3D models from still images

cheers

K


Kevin (and Michael),

basic principle of photogrametry is simple. It is similar to what our brain does all the time: it is using imagery from two slightly offset sources (a.k.a. our eyes) to reconstruct a 3D picture of the environment.

So, if you have two or more photos of the same object taken from various vantage points, it is possible to calculate the 3D coordinates of the points on that objects. Whereas the mathematics of that is fairly simple, the problem in the past was that you 1) needed specially calibrated and practically distortion-free cameras to do that (which were frightfully expensive, think 40.000$ and up), 2) you needed to know the exact positions and orientations of the photos that were taken, which was also not very simple or inexpensive to provide, and 3) you needed expertise and specialized expensive hardware and software to do the reconstruction.

The revolution came with the development of computer vision algorithms, which were originally developed to help navigation of robots in real time (that's why the software doing this is often called Structure-From-Motion or SfM - this is also a helpful search term if you want to look for more info). To do this, you need a large number of photographs taken from different vantage points, but at the same time ensuring a large degree of overlap between the photos - 60% is about the minimum. It's a bit similar to taking images for gigapan stitches, with the main difference that for SfM you must change your vantage point, whereas for gigapan you must not.

With such a set of photos, the SfM software can simultaneously solve all the unknowns: it first automatically identifies points that are simultaneously occurring in several photos ("keypoints" in SfM parlance), and then uses them to calculate their xyz coordinates, to determine camera position and pose (yaw, pitch, roll) for each photo, and even to determine distortion parameters of the lens that was used and correct for those. In the second step, this data is used to calculate precise xyz positions from many more points (the "dense point cloud"), which in turn are used to create the eventual meshed and textured 3D models that you can for example see in my Sketchfab feed.

So basically, at least for simple 3D objects and scenes, the processing is a very simple push-button affair; the critical point is to take adequately positioned overlapping and sharp photos. In a way, the method is similar to high-resolution mode in high-end Olympus cameras - it only works for certain objects and in certain conditions, but results can be spectacular.

The main constraint is that the object must not move during acquisition of photos. In my case, this is simple to ensure, as the rock outcrops are among the most sedentary features in the Universe. (There are people who do fascinating photogrammetric scans of human models, but this is done with an array of 30+ synchronized DLSRs that are positioned around the model so that all the photos are taken at exactly the same time to mitigate any subject movement.) The other constraint is that the surface of the object must not be shiny/reflective, as this confuses the keypoint search algorithms.

As an example, take a look at the Jesus statue (https://sketchfab.com/models/cb4e83b0ab2346f7bf01e51efebd2975) which I did in a demo for the Restoration Centre of our national Cultural Heritage Institute. This was quite tricky because the statue is located in a niche which obstructed the photo acquisition a lot.

Jesus-situation2.jpg
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M43 to the rescue - using my G2 with its articulated LCD and 7-14 lens, I was able to get around and above the statue simply by stretching my arm and thus get quite good coverage (it was a demo after all - in real-world assigment I would have used a ladder or a camera pole).

This image shows the reconstructed camera positions for the acquired photos - each photo is represented by a blue rectangle and a black axis which corresponds to the optical axis of the lens:

Jesus-acquisition2.JPG
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This are some of the photos from this shoot viewed in Lightroom:

jesus-lightroom.jpg
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I hope that this roughly demonstrates how SfM photogrammetry is done?

I highly recommend that you try it yourself, it is not difficult! As you have noticed, I am using a commercial software called Agisoft Photoscan, which is very powerful and inexpensive considering its capabilities, but probably way to expensive for hobby use. Alas, being a lazy Photoscan user I am not that much knowledgeable about the alternatives, but for starters you can try 123D Catch which is a free app/service provided by Autodesk (Autodesk 123D Catch | Generate 3d model from photos) - just follow their instructions.

For more serious involvement you may wish to try several free research-grade applications (translation: very powerful, but not necessarily easy to use or understand):
VisualSFM : A Visual Structure from Motion System
MicMac

Finally, if you want to go deeper than my highly simplified introduction, I recommend the following paper written by a guy who is doing dinosaur reconstructions for a living:
PHOTOGRAMMETRY IN PALEONTOLOGY – A PRACTICAL GUIDE
Check out his blog as well for many practical tips.


Marko
 
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M.V.

Mu-43 Regular
Joined
Jan 16, 2017
Messages
39
Location
Slovenia, Europe
Real Name
Marko
I used to do a lot of cave photography back in the film days as well, in places like PNG and NZ. Should buy a scanner some day to try and salvage some. I notice dye changes have ruined a lot of the colour images.
Haha, a fellow (ex)caver!!! Excellent! Great places that you visited, I envy you!
I was fortunate enough to have purchased the Nikon Coolscan 5000 slide scanner with a slide feeder before it was discontinued, but most of my slides are still awaiting to be processed...

But at least I can offer you a virtual trip to two Slovenian caves :) (or rather a small section of them - this is an ongoing research project), proudly produced with m43 equipment:

Vranja jama by Marko Vrabec - 3D model
Skednena jama osrednji del by Marko Vrabec - 3D model
 

M.V.

Mu-43 Regular
Joined
Jan 16, 2017
Messages
39
Location
Slovenia, Europe
Real Name
Marko
Welcome Marko, a very interesting introduction to 3D! Looks like a lack of snow in the Slovenian Mountains for this time of year?
Hi, thanks!
You are right, up to a few days ago there was an extraordinary meager amount of snow in the mountains, but finally we had some snowfall over the weekend - there's currently 10-20 cm of it in the high mountains from my photo. I would love to share a photograph (those Alps being literally in my backyard so I could shoot it from my bedroom window), but sadly I am sitting in my office at the Uni right now...
 
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M.V.

Mu-43 Regular
Joined
Jan 16, 2017
Messages
39
Location
Slovenia, Europe
Real Name
Marko
what mountain is that you are on?
I used to live at the base of Mangart, on the Italian side (Bela Peč)
Fantastic, that is a very beautiful area, if a little remote. During hot summer days I used to come to swim in the Raibl Lake with my wife and kids.

My photo was taken just below the summit of Mt. Brana in the Kamnik Alps on the Austrian border (Geopedia - interaktivni spletni atlas in zemljevid Slovenije), and view is towards NW.
 
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