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  • help achieving high resolution

    I am new to 3D images but need to create the best possible resolution 3D files of some small rocks. I am using the Lite version of 3DF Zephyr and my usual laptop which is nothing fancy. I am photographing the rocks on a turntable in a white box with diffused light. I can successfully create the 3D image using my smartphone camera and the masking feature. Zephyr seems to accept all of my photos in the photo set when I do this. However, I would like to achieve a better final resolution so I have taken the same photo sets with a DSLR with macro and super macro functions. When I do this, Zephyr only accepts about 10 photos for every 100. I cannot determine why it refuses so many images. Is this likely related to the file size of the photos (my phone produces 1MB files and the DSLR produces 5MB files)? Would tiff files be preferable to jpegs? Is it related to my laptop not having enough processing power? Is it a limitation of the Lite version over the full version of Zephyr? Is it because of the use of the macro functions wherein there is sometimes a loss of depth of focus? Are there any tutorials or suggestions to get better macro images for this purpose? Would a video produce better results?

    My apologies as again, I'm very new to this. I am hoping someone can advise where I should begin with this problem so that I am not trying to correct the wrong aspect.
    Last edited by Amanda; 2020-06-25, 09:32 PM.

  • #2
    Hi Amanda - Welcome to the forum

    To answer your questions:

    - There are many variables to account when it comes to photogrammetric reconstruction. Please share the DSLR dataset using googledrive, wetransfer, or the filesharing service of your choice, and we can give you some targeted feedback.

    - The file size is not really an issue. If your photographs are are very very small or large, this might be problematic, but I've personally used Zephyr to reconstruct images from a range of 5-42mpx with no issue.

    - Shoot RAW and convert to JPG before processing. You can use TIFF, but there's not a significant gain in quality vs. the hard-drive space they take up.

    - Hardware can be a limiting factor when it comes to processing data, let us know your computer specs and we can give some feedback on them.

    - 3DF Zephyr Free/Lite/Pro/Aerial all run on the same core technology, just with different features and toolsets. If a set of photos doesn't work in one, it's not going to work in another.

    - Out of focus images can be problematic. It's important to try and keep as much of your subject in focus as possible.

    - Tutorials and documentation can be found here: https://www.3dflow.net/technology/do...hyr-tutorials/

    - General information for shooting macro: https://www.exposureguide.com/macro-...aphy-tutorial/

    - Video is more problematic than photography, as there are additional steps required to extract frames from the footage. It's easier to process photographs and they will almost always give better results.

    Happy to answer any more questions you might have!

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    • #3
      Thank you, cam3d. This is very helpful. I have switched to a macro lens and will attempt some improved photo sets with better focus based upon the tutorial you linked. I'll post those photo sets and the computer specs after I try that. Your response is much appreciated!

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      • #4
        No problem - Happy to look at the data whenever you are ready

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        • #5
          I switched to a macro lens but am still struggling to get an entire rock in focus simultaneously. I assume this is most of my problem and the reason the software is kicking my photos back and that I'll just need to continue adjusting the camera set ups. I have added two of my photo sets to the below links. The pyrite was done with the macro lens. The software accepted only 16 of the 163 photos. Again, I assume because the subject isn't entirely in focus in any of them. The lava set was taken with my Galaxy S9 and the Zephyr accepted all of the photos. This turned out well except that it lacks the resolution I was hoping to achieve.

          Other than working on the set up for the DSLR, are there any other possibilities? Could I mask out the out of focus portions of the photos, and assuming I have enough remaining overlap, expect to have Zephyr accept those? Would a 3D scanner achieve my goals? I have not looked into one and perhaps those are outside the realm of this software, but the appeal seems like it would overlap so maybe someone here has tried that?

          Thanks for any additional guidance.

          https://drive.google.com/drive/folde...sS?usp=sharing

          https://drive.google.com/drive/folde...MF?usp=sharing
          Last edited by Amanda; 2020-07-01, 03:46 PM.

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          • #6
            Amanda - You don't need the entire subject in focus, but it does help a lot!

            Can you please open access to those file downloads? Currently they are password protected Thanks!

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            • #7
              Sorry about that - I thought they were shareable. I think they will work now. Thanks!

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              • #8
                Hey Amanda Thanks for sharing the dataset - For some reason google drive isn't letting me download the whole sets to test, but I can give you some pointers based on a sampling of the images:

                - The Pyrite is taking up a very small part of the overall image so you're really only working with approx 640*800px subsections of the overall 4928*3264 image.

                - Metallic surfaces are incredibly hard to capture using photogrammetry because light dances across the surface and is inconsistent. You could try dusting with a fine powder (talcum powder is great for this) which will reduce the reflections and add more feature points for Zephyr to lock on to. I can't stress enough though, metallic surfaces are a real pain to get right.

                - These images look a bit under-exposed (assuming the background is white) - My personal preference is to work with a black background as it absorbs shadows and unless your object is very dark, it's a good way to get separation between the subject and the background.

                - Your F/Stop is very low for macro work, so your DOF is slim. I would increase F/Stop from 5.6 to 11 or higher to get more of your subject in focus.

                - Masking extremely out of focus parts could be somewhat beneficial, but if something is slightly out of focus in one shot, and in focus in other shots, it's not such a problem because Zephyr will typically pull information from the consistently in focus elements of the subject.

                - If you can avoid getting your hand in the shots, that would be ideal, using something small to prop up the subject works well, though it does depend on the subject.

                --------------------------------

                - With the lava, your shutter speed changes midway through the capture (1/40 > 1/120) ideally this stays the same for the sake of consistency.

                - The lava is larger and isn't particularly shiny or metallic, which is why its easier to capture than the Pyrite, not because of the camera used.

                --------------------------------

                You can merge third party 3D scans with photogrammetry in Zephyr, but it can be a bit finicky to get perfectly aligned - It depends a lot on the third party scan data accuracy, and would require 3DF Zephyr Pro/Aerial.

                --------------------------------

                If you have them at your disposal, brighter studio lights would be beneficial because you can increase your F/Stop to 11 + without having to increase your iso or lower your shutter speed. This, or going outside and scanning on a bright, but cloudy day. The clouds help to defuse the light evenly and the sun is considerably cheaper than studio lights.

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                • #9
                  Thank you so so much! This is all helpful. I have ordered additional lighting and I have black back drops I can swap in as the end goal is actually to get a quality 3D rendition of mostly white minerals. I was just playing around with ones I have handy so I will certainly avoid the metallic pyrite while practicing. I'll try your recommendations for the photography and get a better data set. Thank you!!

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                  • #10
                    Great! Glad to be able to help! Hope the lights and backdrop arrive soon so you can use them to their full potential If you get stuck at any point in the process feel free to ask any questions (I've had a lot of practice setting up lights for photogrammetry )
                    Last edited by cam3d; 2020-07-03, 06:16 AM.

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