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Sigmund

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Everything posted by Sigmund

  1. Sigmund

    Photogrammetry

    Hi, I hope a question concerning photogrammetry is not out of space here? This topic appears in some postings and thus I dare to ask the following: In addition to RTI I would like to create 3D-models and for now I made some tests with Autodesk 123D. There are two features I need for my research: I need to make high resolution snapshots and I need to change the original colour of the surface in the model. Can somebody recommend freeware for these purposes? Has ARC3D these functions? Thank you! Sigmund
  2. Sigmund

    ARCTRON

    Hi, does anybody know the photogrammetry software and information system "aSPECT3D" from the German company "Arctron"? Does anybody have experience with it? Here are some links: http://www.arctron.de/en/products/software/aspect_3d/ http://www.ifp.uni-stuttgart.de/publications/phowo13/200Schaich.pdf Sigmund
  3. Hi! Until now I worked with carved stones in a museum. Today I made RTIs of an erected carved stone outside for the first time. The results are OK but when I zoom in I realize that it is slightly blurry. I use a good tripod for the camera and two cheap microphone stands for the spheres. The stone was erected in a kind of garden so the stands and the tripod were standing on grassland - I tried to fix them as firmly as possible. Today it was quite windy. Not really stormy but it was blowing quite strong from time to time. Now I wonder if the wind could be the reason for the slightly blurry results? Does anybody have similar experience? In addition, I turned the image stabilization (steady shot) out. This can't be the reason, can it...? Thanks for all replies! Sigmund
  4. Sigmund

    Camera Angle

    Hi, in the mode Specular Enhancement some of my PTMs look "grainy" or "sandy": Now, I realize that this appears to depend on the camera angle. The camera should be at 90 degrees from the subject. In the "grainy" cases I had to change the camera angle in order to catch figures on the upper part of my erected carved stones. Can anyone confirm this observation or does it rather depend on the power of the flash light (too much light?)? Thank you!
  5. Sigmund

    Strange grid on PTM?

    Hello, perhaps this issue was already discussed but I could not find it on the forum: I recently realized that on some of my PTMs there is a very faint grid. I do not like that! Did I make a mistake during the capture or might it just depend on my laptop screen??? Thank you for any ideas Sigmund
  6. Sigmund

    Strange grid on PTM?

    Hello and thank you, I tried to make snapshots but you can not see this very faint grid on the snapshots. I more and more believe, that it has to do with my screen... Sigmund
  7. Sigmund

    Camera Angle

    Concerning my "grainy" results I agree with George: This is a different problem. I tried it again and again but the result is always grainy. However, other PTMs I made during the same working day on the same location are OK! In addition, I realized that in a single case I obtained grainy PTMs also in the Museum (indoors). My conclusion for now: It appears to depend on the surface structure. Some of my stones course grainy PTMs, most of them not. Not satisfying but apparently true.
  8. Sigmund

    Camera Angle

    Dear Marlin and George, thank you! It is good to know, that it has nothing to do with the angle. First I will try to kick out the brightest images. Next week I can do the entire capture again. I have to add, that I made the capture outside and from time to time the sun came out. Could the sun be the reason? Usually, I work indoors. I really hate these grainy results, I can not work with them. Concerning Marlin's question: These are Viking stone slabs made of lime stone. The depictions are made in a quite low and primitive relief, today it is hardly weathered. The stones were painted by researchers in recent times.Therefore, I have to turn out the colour in order to see the original carving. This normally works with Specular Enhancement. Unfortunately, with Specular Enhancement the grainy PTMs look terrible. Sigmund
  9. Dear Taylor, thank you for your advice! I tried it today - it was windy - with weights and the results are perfect. Techniques for aligning the images would be a very helpful thing. I will try PTGui - thank you. CHI is working on a tool? This is interesting. Can anyone tell more about it? Best regards from the Baltic Sigmund
  10. Sigmund

    Photogrammetry

    Hi, thank you for your replies. I tried to make better images. The results are really good - I would say: https://www.dropbox.com/sh/1pdurml53znovvf/hzRG31OmIj
  11. Sigmund

    Photogrammetry

    Hi, in Autodesk you can refine your models to standard or maximum quality. However, when I submit photos with 16 megapixels this does not work. I asked Autodesk and they wrote me: "Sorry for the confusion. Please do not submit images higher than 6 megapixels. Any images higher than this may be able to process at mobile mesh setting, but run into issues when processing at a higher mesh (standard, maximum)resolution. When you submit photos between 3-6 megapixels, you can process at any of the desired mesh resolution settings (mobile, standard, maximum). For best results, and what I do, I submit 6 megapixel images. Then, when I get my result, I select the part of the mesh I am focused on and resubmit at a higher mesh resolution setting. When you resubmit for a different mesh resolution and have a portion of the mesh selected, only the bounding box of that mesh will be reprocessed at the requested mesh processing setting." I wonder if it is better to make photos with 16 megapixels and let the model how it was created or to make photos with only 4-6mp and then refine them to maximun quality. I have to admit, that I do not really understand the difference. How do I get the best model??
  12. Sigmund

    Photogrammetry

    Thank you for all these tests and information! These photos were just some samples. Here I have more photos of a detail of the second stone and the model I made with Autodesk 123D catch: https://www.dropbox.com/sh/1pdurml53znovvf/hzRG31OmIj I will make new and more photos today and next week! Did I understood correctly, that I should try to make all photos from appr. the same distance, without changing the focus? For the second set of photos I tried to do not refocus at all. Is that really necessary? ANother question: How many rotations with which angles would you recommend? I made two rows, one a little bit from above, one a little bit from below. Perhaps 110° and 70°. George - you worked with the Gotland picture stones? Tell me more about it! I'm here for three months and my aim is to document the most interesting slabs with RTI and perhaps photogrammetry. In Gotlands Museum I'm ready for now with RTI and I just started there trying photogrammetry. It was hard work because I had no assistance and the slabs are erected. I only made small portions, appr. 30-40cm, so I could manage the measurements. Here is an example: For all who are interested in the stones in general, I put my new article into the photo folder.
  13. Sigmund

    Photogrammetry

    Hi, OK, I have to admit, that I do not use dropbox often. Does this link work? https://www.dropbox.com/sh/dfzu0ju1jevxl1f/ux-QbNiE0Q What can you tell about the focus? Do I have to use manual focus, auto focus and is it advisable to focus always the same point in all images? Here I have another sample, made with 4 megapixels and manual focus: https://www.dropbox.com/sh/1pdurml53znovvf/hzRG31OmIj
  14. Sigmund

    Photogrammetry

    Sorry for answering late! Here is a folder with some of the pictures: https://www.dropbox.com/home/Bro%20Kyrka%20I_Photos I use a Alpha 55 with a 2.8/50 Macro. In this case I used the auto focus. Lightsource was the sun. Unfortunately, the images are not very detailed. I also made some photos of certain details but I don't believe that Autodesk will be able to fit them in. Please check them, I can easily make new pictures, this would not be a problem! Sigmund
  15. Sigmund

    Flash Light Distance

    Thank you!
  16. Sigmund

    Flash Light Distance

    The objects I try to document are erected stone slabs. I have to document carvings in the lower parts of the slabs, near to the ground. For this reason, I often have problems to keep the distance between flash and stone surface. The distribution looks like that: Surprisingly, I can not see any decrease in quality. The RTI viewer does its job, I see no difference. When I make a PTM of the same set of images, however, I notice that some light directions are underrepresented. In particular in the mode Specular Enhancement. Does anyone have similar problems? Is it better to leave off certain parts when the distance can not be kept (as I did) or do you always take the longest distance possible, even if it is relatively short? Sigmund
  17. Sigmund

    Flash Light Distance

    Taylor, thank you so much! It is great to have people here who share their experiences. Sigmund
  18. Sigmund

    Flash Light Distance

    Hello Taylor, thank you for your reply, it was helpful. Good to hear, that others made similar experiences. Did I understand correctly, that I can use different distances between light and object in one capture, if necessary? Do you also reduce the light intensity in those cases? Reducing the area of the subject and making some more RTIs seems to be the best way. My best results are always with quite small portions. Another reason for making smaller RTIs is: Most of the time I'm alone and without any assistance. If I had longer distances, measuring becomes extremely difficult or even impossible. The areas I choose now are about 30cm, the distance then is 90-120m. This works, even when I'm alone. Testing the spreadsheet and the PTM planner would be wonderful! Sigmund
  19. Sigmund

    Photogrammetry

    George, this looks amazing! If you could help me to do something similar with my stones I would be deeply grateful. I have a set of about 70 images. I only made images of the entire stone, no images of details. The pictures have 16 megapixels. Is that OK or should I make new images? As far as I know, Autodesk has problems with images more than 6 megapixels. We can use the dropbox if you want. Sigmund
  20. Sigmund

    Photogrammetry

    Tom, thank you for sharing your experiences, this was helpful. As you said, it is really, really time consuming to try and test these things. The buttom line appears to be, according to your experience, that all these services/softwares provide good results - as far as the images meet certain requirements. Nevertheless, I would like to make the tests as George suggests. I would like to test 123D catch, let's take Taylor's images. Sigmund
  21. Sigmund

    RTI Viewer: Resolution and Colour

    Wow! I underestimated the ptm viewer. I will explore it!
  22. Hello, I'm a RTI beginner so my first questions might be foolish. My first RTI results are good but, comparing them with the video examples on the CHI homepage, two things are still disappointing: 1. I can't manage to take the colour out as in the videos. My objects are painted stones. I would like to take out all the colour so that the painted parts disappear. However I try to change the setting with Specular Enhancement - there are always gleams of the original colour left. 2. In the videos the RTI viewer can zoom in very much. This is not the case with my RTIs. Is this a camera problem? Another question I have on my mind is: Has the PTM viewer any advantages over the RTI viewer and where can I download it? Sorry for asking foolish questions and thank you! Sigmund
  23. Sigmund

    RTI Viewer: Trackball

    Thank you!
  24. Sigmund

    RTI Viewer: Trackball

    Hi, here is a beginner's question once again: In some of my RTIs the light changes simultaneous when I touch the trackball. In other RTIs there is always a delay. This makes working with the RTI difficult. Can anybody tell me wheather this just depends on my memory or on the quality of my capture?! Thanks! Sigmund
  25. Sigmund

    Photogrammetry

    This is a great idea, count me in. How can we arrange it?
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