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Re: [Openexr-user] Re: How to combine multiple exposed images? (Josef Gr
Re: [Openexr-user] Re: How to combine multiple exposed images? (Josef Grunig)
Tue, 04 Oct 2005 12:15:06 -0700
Mozilla Thunderbird 1.0 (X11/20041207)
you may find this paper on Paul Debevec's web site interesting:
From the abstract:
We present a method of recovering high dynamic range radiance
maps from photographs taken with conventional imaging equipment.
In our method, multiple photographs of the scene are taken
with different amounts of exposure. Our algorithm uses these
differently exposed photographs to recover the response function of
the imaging process, up to factor of scale, using the assumption of
reciprocity. With the known response function, the algorithm can fuse
the multiple photographs into a single, high dynamic range radiance
map whose pixel values are proportional to the true radiance values
in the scene.
Well....you've asked a question that could fill volumes with an answer,
but the basic idea is that you take a series of images that are shot at
differing exposures (changing the shutter speed NOT the aperture, which
causes focus problems) and combine them into one 32 bit high dynamic
There are two pieces of free software that you can use to build an HDR
image from multiple exposures:
Greg Ward's Photosphere available for OSX here: http://www.anyhere.com/
Paul Debevec's HDR Shop V1 which runs on Windows available here:
The new version of Photoshop CS will also assemble HDR images....and
there is a newer version of HDR Shop V2...but you will need to purchase
both of these programs.
The HDR Shop website has a really great set of tutorials on the
how/what/why of HDR images, I'd start there. And then if you want to
get into the application and use of HDRI and Image-based Lighting:
there's an amazing amount of reading material on Paul Debevec's site:
This should give you a good start.
Hi to all,
I'm a newbye to OpenEXR and would like to create my first HDR image.
I've read that a way of creating HDR images is assembling multiple
exposed (with different f-stops) images. I didn't find how this
"combining" has to be done. Can you tell me more?
Thanks a lot!