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7th January 2020, 15:41 | #3 | Link |
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I'm afraid your answer is too short for me to understand.
What I mean is something like the pics shown here: https://webuser.hs-furtwangen.de/~de...Panoramas.html In my simple words: How would a scene look like if not taken with a wide angle lens but with telephoto? Of course it would be a kind of "artifical" result (due to hidden/ unrevealing effects). In image manipulation I do have the "panorama tools" (as plugin). Changing the FOV changes a grid to a kind of spherical projection (and vice versa). You do find me confused. |
7th January 2020, 16:57 | #4 | Link |
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I'm not aware of any for vdub . But shotcut (free, open source) has the bigsh0t plugin, which can manipulate several types of projections, FOV adjustment . Since it's a NLE, adjustments are keyframeable (changes over time) and you can "see" what you're doing with feedback . (There are more complicated open source programs like natron that can do this too)
Make sure you download the 2.1 release https://monochrome.sutic.nu/2018/09/17/bigsh0t.html https://bitbucket.org/leo_sutic/bigsh0t/src/master/ "The artist formerly known as DH" also wrote the avisynth plugin defish with FOV adjustments https://forum.doom9.org/showthread.php?t=152860 |
7th January 2020, 18:32 | #5 | Link |
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You're confusing two concepts - changing the projection and changing the FOV. You can change the projection easily enough, but you can't change the FOV of an image (except for the trivial case of cropping, but then you're deleting information).
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7th January 2020, 19:59 | #6 | Link |
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I assume you do mean both of us?
Yes, I do agree, I also have the impression that I'm confusing the two concepts. Because actually I do not understand why it should be a problem to change FOV. To quote from my post #3 from above: How would a scene look like if not taken with a wide angle lens but with telephoto? Of course it would be a kind of "artifical" result (due to hidden/ unrevealing effects). Well, it's showy that there can't be found such a filter. And even the panotools don't offer a ... "FOV conversion". Only a changing from one projection to the other, and to specify FOV for rectangular. (BTW. What if I would map from a rectangular with FOV_src to fisheye, then back from fisheye to rectangular with FOR_dst?) In OpenGL there seems do be a method for FOV changing, to do the dolly effect for example (??). |
7th January 2020, 21:54 | #7 | Link | ||
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Changing the FOV of an image, other than simply cropping or expanding (which is just deleting or inpainting information, and doesn't change the FOV of the actual content), means changing the (virtual) distance to the camera - and that means reconstructing the scene in 3D. And if you can do that, you may as well just have whatever AI you've used to stabilise the camera motion for you and re-render it entirely.
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7th January 2020, 22:11 | #8 | Link |
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Believe it or not ... I do understand that. Thank you!
But then I'm really wondering what kind of magic you do in your AviSynth plugin. It uses the FOV, but hasn't the 3D info. BTW: As far I know now your plugin is the only one that does the trick. It's a pity it can't take rolling shutter effect into account, and can't exclude/ refill areas (borders, logos etc.). So you have unsteady moving border/ dubbing-ons. EDIT: Maybe the "distorted projection" I described above (doing directly without the detour to fisheye of course) would result to better results when DeShaking wide angle movies? Last edited by nji; 7th January 2020 at 22:28. |
12th January 2020, 13:42 | #10 | Link |
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Rethinking the idea from my other thread:
Making spherical projection before deshaker analysis...would probably favor all direction rotations, zoom so so ...but definitely not moving the camera (changing to PoV x and y axes) |
12th January 2020, 14:02 | #11 | Link |
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If there is spherical projection suitable for rotation and for example rectangular projection for camera movement... why not run on one video deshaker for two projections after each other.
I didn't give it second thought. Do i smoke too much? |
12th January 2020, 17:28 | #12 | Link |
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Changing from one central projection to another central projection is more or less fail-safe as long as you keep the center the same. Once you move PoV you need distances to pixels and also reconstruct revealing areas. This is much more challenging. AFAIK this part of research is called "structure from motion".
Have you tried to find any software which already does that? Like Microsoft Hyperlapse for example.
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12th January 2020, 19:03 | #13 | Link |
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nji: Maybe something like defish() will help to achieve what you had in mind.
Edit: I'm too late to the party, I just saw poisondeathray's post.
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13th January 2020, 08:38 | #17 | Link | |
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So, defish doesnot change the projection? Just straightens lines etc. a little? So, in that case... ... how do I apply that projection change script with xyreap? https://forum.doom9.org/showthread.php?t=171922 Last edited by redfordxx; 13th January 2020 at 08:42. Reason: https://forum.doom9.org/showthread.php?t=171922 |
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13th January 2020, 16:44 | #18 | Link | |
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"Straightening lines" - the way it's done with any of these types of filters - is changing the projection. So is causing lens distortion. Any type of lens distortion manipulation that causes "warping" in post is , by definition. But it might not fall neatly within some named category Why are you doing this ? The common reason is to reverse the lens distortion, do whatever manipulations, then add back the same lens distortion (if desired) to match the original footage. The reason is many types of manipulations require flat or equirectangular to work properly. Compositing for example. If you can't get what you want with one of those listed above, try natron. It's got several models in it's lens distortion node including panotools |
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13th January 2020, 18:07 | #19 | Link |
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Sorry maybe for me being slow:
I made defish using a,b,c parameters. Now I am asking what is the resulting projection supposed to be? Rectangular? Because when I am going to change the projection using the tools mentioned, I need to know what I am starting with. That's what I've asked few posts above. |
13th January 2020, 18:27 | #20 | Link | |
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????? Maybe I'm the one that is slow... It can be anything depending what your values are , and what you start with eg. If you start with "normal" equirectangular projection, you can impose a lens distortion. Create one. If you start with a "fisheye" you can "undo" it or make it more pronounced (pincushion / barrel) . You can do whatever you want If you cannot find your camera lens profile somewhere, if you don't know what you have - normally you would need to do a lens calibration. Essentially you shoot a grid pattern. Then measure or estimate what you have. Last edited by poisondeathray; 13th January 2020 at 18:36. |
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Tags |
field of view, filter, fov |
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