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taking 360 panoramic HDRI's
show user profile  zeefusion
Hi all,

I am going to be soon trying my hand at taking 360 spherical HDRI images and I wondered if any has any tips? My basic understanding is this:

1. Mount camera on the tripod and with a 180 degree fish eye lens take 3/4 bracketed exposures.
2. Turn the camera 180 degrees and repeat the above process.
3. Use software to stitch the two 180 images for each exposure to create a 360 degree image.
4. Use Photoshop to generate the HDRI form the 3/4 36-0 degree images.

Questions I have are:
1. Do I need to do anything with the lens to create the correct 180 degree spherical view and do I need to take into account any distortion?
2. What software is best to stitch two 180 degree images together, Photoshop?
3. Is it best to shoot in RAW and adjust exposures manually in camera RAW or similar software to get 3/4 different ones or use bracketed exposure and save out TIF's or JPEG's?
4. Can I just turn the camera on the tripod but keep the same spot in the room?

Thanks :)




read 1368 times
8/15/2012 12:45:19 PM (last edit: 8/15/2012 12:45:19 PM)
show user profile  twitt
http://www.autopano.net/wiki-en/action/view/Stitching_fisheye_photos





read 1322 times
8/15/2012 4:25:20 PM (last edit: 8/15/2012 4:25:20 PM)
show user profile  zeefusion
good resource, thanks.
read 1307 times
8/15/2012 5:25:36 PM (last edit: 8/15/2012 5:25:36 PM)
show user profile  reeves1984
You'll probably need to take more than just 2 directions, even if it is 180deg. I have a fish eye lens (not 180 deg) and just cover what I need to. I don't do it reguarlly enough to say precisely!

1. Software should take care of the distortion for you.
2. PTGui is pretty good!
You could use photoshop.. for one exposure at a time (or at least thats what I did years ago)
3. I did investigate this myself, why take 3 photos when you can use 3 different exposures from a Raw?
Because it needs to be done manually, or have some automated process. And taking 3 jpgs isn't exactly a challenge to deal with.
4. Yes. But if you want to be mega precise and spend money you can get pano heads for tripods which spin on the point of the sensor ! http://www.manfrotto.com/panoramic-head

In the end having a perfectly stitched map might not even be super important. Depends what it's for!

(If you have to shoot one quickly on location and in the end you can't get it perfect, you don't have to throw it away, put it that way)


--
Simon Reeves


www.simonreeves.com - VFX Artist & Blog
twitter


www.analogstudio.co.uk <-- I work here

read 1293 times
8/15/2012 7:32:21 PM (last edit: 8/15/2012 7:33:14 PM)
show user profile  zeefusion
Thanks for the help. However if taking more than two photos how do you go about getting this?

read 1272 times
8/16/2012 9:28:02 AM (last edit: 8/16/2012 9:28:02 AM)
show user profile  reeves1984
I'm not sure what you're asking, it's no different using 2 or more, the application takes care of the merging

--
Simon Reeves


www.simonreeves.com - VFX Artist & Blog
twitter


www.analogstudio.co.uk <-- I work here

read 1268 times
8/16/2012 11:15:49 AM (last edit: 8/16/2012 11:15:49 AM)
show user profile  zeefusion
The above image to me looks like it was created from two images using the fish eye lens. One facing one way and the other facing the opposite. which gives two distinct circular distortions

In my head I am thinking if you take more than 2 fish eye photos and merge them together it will end up with more than 2 circular distortions.

Unless as you say the software takes care of that for you? I don't doubt I am wrong as this is all new to me :)
read 1263 times
8/16/2012 11:27:36 AM (last edit: 8/16/2012 11:27:36 AM)
show user profile  reeves1984
Ah ok I see what you mean..

But no, that's how any spherical pano image will look :)

--
Simon Reeves


www.simonreeves.com - VFX Artist & Blog
twitter


www.analogstudio.co.uk <-- I work here

read 1261 times
8/16/2012 11:31:21 AM (last edit: 8/16/2012 11:31:21 AM)
show user profile  Dub.
Get PTGui, it is worth the money and is by far the best stitching tool.

It specifically handles the 180 degree fisheye images as well - not all stitching programs do.

Once you have it and if you are still stuck I'll give you a hand.


read 1257 times
8/16/2012 11:33:23 AM (last edit: 8/16/2012 11:33:23 AM)
show user profile  zeefusion
So with PTGui I take two 180 degree fish eye images. Or do I take multiple lesser degree images and stitch them together? Or does it not matter, either way it will spit out like the example?

Thanks for the help

*edit" Herehttp://www.ptgui.com/hdrtutorial.html
there is no mention of using a fish eye lens so is it not needed then? Can I create a spherical HDR without?
read 1254 times
8/16/2012 11:36:57 AM (last edit: 8/16/2012 11:41:11 AM)
show user profile  zeefusion
Hmm this guy is talking about taking 300 photos for a single HDRhttp://forums.cgarchitect.com/22850-360-spherical-hdr-tutorial.html

read 1245 times
8/16/2012 11:46:15 AM (last edit: 8/16/2012 11:46:15 AM)
show user profile  reeves1984
You just need to cover everything. The wider the lens, the less photos you'll need.

--
Simon Reeves


www.simonreeves.com - VFX Artist & Blog
twitter


www.analogstudio.co.uk <-- I work here

read 1244 times
8/16/2012 11:46:24 AM (last edit: 8/16/2012 11:46:24 AM)
show user profile  reeves1984
More photos = higher res

--
Simon Reeves


www.simonreeves.com - VFX Artist & Blog
twitter


www.analogstudio.co.uk <-- I work here

read 1239 times
8/16/2012 11:49:32 AM (last edit: 8/16/2012 11:49:32 AM)
show user profile  zeefusion
OK cool thanks
read 1238 times
8/16/2012 11:49:37 AM (last edit: 8/16/2012 11:49:37 AM)
show user profile  Dub.
If you are just taking 2 images, you won't have any pixels that overlap. In that case you can use a program such as Nuke to convert your fisheye image circles to cylindrical mapped squares. In theory all you need to do is take both your fisheyes, transform them to cylindrical and then they should match when placed side by side. In practice you will have to correct for any camera misalignment and lens vignetting. Usually a bit of painting over the seam does the trick.

If you want flawless results, you'll need to take at least 3 images. This will give you significant overlap and PTGui will have no trouble stitching them.

The fisheye options in PTGui appear when you tell it right at the start that you are using a fisheye lens. It will give you a crop circle so you can tell it where your image circle is. Be as accurate as possible at this step. A small error here can result in quite a lot of distortion in the final unwrapped image.


read 1209 times
8/16/2012 9:33:17 PM (last edit: 8/16/2012 9:33:17 PM)
 
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