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Can hugin use exr input to produce exr output? (Read 1011 times)
raveled
Ex Member


Can hugin use exr input to produce exr output?
02/21/13 at 07:16:25
 
I tried Hugin for the first time about a week ago, and quickly realized that the brightest exposure from one bracket set was often impossible to find control points for on the darkest exposure of the next set.

I decided I'd just merge to exrs ( then remove dust, white balance and expose just one exr rather than remove dust from 5 plus jpegs ( then stitch them into an hdr pano. )

I tried it last night and it crashed about 20 times.

I found this:

" Can I stitch my HDR images ?

Yes. If you already have merged your HDR stacks, follow the Normal Output on the Stitcher tab (HDR merging is for stacks that will be merged by Hugin). In the Processing step the output will be an HDR in TIFF format."

On the panotools wiki.

I'm not sure what they mean by "normal" is it the default settings?

I'd ideally like to save them as exr for IBL work in Blender, is a tiff HDR REALLY and HDR? Does it support 32 bit FP?

I also found myself questioning my lens and projection settings.

I have a Rokinon 8mm "asphereical fisheye" lens that is made for my ASP C Samsung NX 200.

So normally it's considered a 1.5 x crop factor, but it claims to be a 180 degree full frame lens for asp C sensors.

So in this case which FOV, crop factor should I use?

Adding the 1.5 crop factor reduces the FOV to much less than 180 degrees, so I'm not sure if I'm setting it correctly.

Another thing I'm wondering is the projection type, Christian mentions the 8mm Rokinon lens as having stereographic projection, is that correct for my lens?

Lots of questions, anticipating any of these settings may mess with stitching and cause crashing.

I hate to admit that I'm sure this is why people buy PTGUI Pro, and I probably eventually will, but is there any way to use exr inputs in Hugin to produce a true HDR output for IBL? Especially without crashing;-)-

Thanks,
       Tim

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Rork
Ex Member


Re: Can hugin use exr input to produce exr output?
Reply #1 - 02/21/13 at 16:08:38
 
Never gave Hugin much more testing than a couple of crashed sessions.

If you have shot everything on a tripid, and I assume you did, try to see if there's something in Hugin to 'link' the exposures together before stitching.

PTGUI has this option, and it works really really well. Because as you found out, at some point the bracket is too dark or too bright to stitch properly.

The lens: not checked this, but if it's made for a APS-C camera, there's no crop factor as the lens is designed for the smaller sensor.

Hugin output: 32 bit TIFF can be converted to a 32 bit .exr or .hdr. Keep the image 32 bit at all time, or you will loose the lighting information for Blender later on. Just be sure the endresult is a so called 'latlong' image, a 360x180 dgr. 'stretch'.

Hope this helps.

rob
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raveled
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Re: Can hugin use exr input to produce exr output?
Reply #2 - 03/17/13 at 06:16:34
 
Never gave Hugin much more testing than a couple of crashed sessions.

True, after 5 ish plus completely reliable crashes I realized that buying it was a better time investment than hoping for one out of six successful panos while putting time into 6 to get it. So I bought PTGui.


If you have shot everything on a tripid, and I assume you did, try to see if there's something in Hugin to 'link' the exposures together before stitching.

PTGUI has this option, and it works really really well. Because as you found out, at some point the bracket is too dark or too bright to stitch properly.

COOOOL, how do I set that option on PTGui? It seems to work amazing better than Hugin anyway, but it would be SOO handy to have it group them together:-)


The lens: not checked this, but if it's made for a APS-C camera, there's no crop factor as the lens is designed for the smaller sensor.

I'll try that out, I've been using a crop factor based on the sensor size, and everything seems to work out, but I'll see if it works equally without using a crop factor.


Hugin output: 32 bit TIFF can be converted to a 32 bit .exr or .hdr. Keep the image 32 bit at all time, or you will loose the lighting information for Blender later on. Just be sure the endresult is a so called 'latlong' image, a 360x180 dgr. 'stretch'.

Hope this helps.

Yes in deed it does Rob, even though I bought PTGui, I have two new features I wasn't aware of. One more question, why 360 x 180 and not 360 x 350?


rob

Thanks for you help Rob,
Tim
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Rork
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Re: Can hugin use exr input to produce exr output?
Reply #3 - 03/17/13 at 09:53:25
 
In PTGUI it's under Images>Link HDR Bracketed Exposures

That way PTGUI will assume you shot with a tripod, and link all separate sets of images together.

360x180 is a full panorama. When using an HDR for CG lighting, this is the way of shooting/creating an HDR. You want all of that lighting information, and with a 150 dgr. you're missing out on a bit of sky/floor Wink
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