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Tutorial for Defishing 8mm Pro with Hugin?

Discussion in 'Image Processing' started by Lcrunyon, Sep 20, 2015.

  1. Lcrunyon

    Lcrunyon Mu-43 Top Veteran

    758
    Jun 4, 2014
    Maryland
    Loren
    I'm trying to learn how to Defish images taken with my 8mm Pro, using Hugin. I admittedly struggle with Hugin's interface anyway, but I usually can muddle my way home through panorama stitching, even if my efforts are not always successful.

    I did read a tutorial about it here, but from I can gather, I need to be able to enter specific data about how I want the image to turn out, and I don't really know how I am supposed to arrive at that. Is it lens specific? Does the starting aspect ratio change things? Are there any particular rules or settings I should be following?

    Sorry for the overly-broad questions. I don't even know enough at this point to ask the right questions.
     
  2. Lcrunyon

    Lcrunyon Mu-43 Top Veteran

    758
    Jun 4, 2014
    Maryland
    Loren
    So, as I practice more, let me provide a little more context. I've figured out some of the basic process, but my images are coming out only perhaps halfway defished. That's even after using the stitcher tool to mark what I want to be straight vertical lines. For landscape images where I don't have any straight lines to work with, I don't really know what to do.
     
  3. siftu

    siftu Mu-43 Top Veteran

    636
    Mar 26, 2015
    Bay Area, CA
    siftu
    I haven't had much success with Hugin and defish eye but I also didn't spend much time with it. I have some LR presets which go a little ways, the rest I do in photoshop. Do you have an example image? A lot of the landscapes you really cant tell that much
     
  4. Lcrunyon

    Lcrunyon Mu-43 Top Veteran

    758
    Jun 4, 2014
    Maryland
    Loren
    Here is one I tried just for practice. The versions don't look all that much different, but I left one side uncropped to be sure. You can see that the first one is a bit straighter than the second, but still not completely straight.


    image.


    image.
     
  5. Lcrunyon

    Lcrunyon Mu-43 Top Veteran

    758
    Jun 4, 2014
    Maryland
    Loren
    Here is a landscape one, but I couldn't get it to defish because I don't know how to handle it if there are no straight lines. For this one I was going for a distorted effect, so I can understand if it would be too much to defish successfully. But even if it wasn't so distorted, what would be the process for defishing? image.
     
  6. PacNWMike

    PacNWMike Mu-43 Hall of Famer

    Dec 5, 2014
    Salish Sea
    guess?
    Well, first I would try hugin's straighten tool. Or you can choose the Move/Drag tab and drag things the way you want. Or try different projections...fisheye?
     
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  7. tkbslc

    tkbslc Mu-43 Hall of Famer

    To de-fish, you want to change the projection. Moving the center only changes where the fisheye distortion starts from. You aren't actually removing any of it unless you change projection.

    I typed this up for someone on another forum a while back, so I'll cut and paste it here. it's a quick and dirty guide to defish with hugin.

    1. open Hugin

    2. click on the blue "GL" icon for guided panorama (you are making a 1 shot panorama basically)

    3. Open your image. It will ask what focal length and crop factor. Also tell it that it is a full-frame fisheye lens in the lens type. (you will put 8mm (or 7.5 depending on lens) and 2x crop factor and choose full frame fisheye and it will calculate HFOV for you)

    4. After image opens switch to projection tab and mess with the different projections. Rectilinear, Trans Mercator, Stereographic and Panini General seem to be my most used.

    5. If you have issues with curved buildings or horizon, you can use the "move/drag" tab to try and change the center of the photo projection and fix leaning verticals.

    6. On the crop page, choose auto crop and it will pick the largest possible crop for your photo. Usually an odd aspect ratio.

    7. Switch back to main Hugin window and switch to the "stictcher". Click on "calculate optimal size" and "fit crop to images"

    8. Hit stitch at the bottom right and pick your output settings for file type and location.

    *Bonus tip: Use the undo feature if you run into weird issues where it turns into a crazy wide bar or something.

    Sounds more complicated than it is and I feel it is the BEST solution for defish, regardless of the freeware aspect​
     
    Last edited: Sep 20, 2015
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  8. SojiOkita

    SojiOkita Mu-43 Top Veteran

    617
    Feb 23, 2014
    France
    I made a quick tutorial for the 7.5 mm fisheye here:
    https://www.mu-43.com/threads/78059/#post-789995

    Should be the same for the 8 mm apart from the focal length.

    I find that most times the Panini projection is more pleasant than the rectilinear projection.
    Stereographic is great too.
     
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  9. Lcrunyon

    Lcrunyon Mu-43 Top Veteran

    758
    Jun 4, 2014
    Maryland
    Loren
    I am starting to think the Windows and Mac versions are very different, with the Windows version offering a more user friendly interface. The version of Hugin I've been using from the internet doesn't look the same as I see on the tutorials.

    I am out taking pics in Hawaii for a week, so I'll try defishing more when I get back, and utilize some of the advice you all have provided. Thanks!
     
    Last edited: Sep 25, 2015