POV-Ray : Newsgroups : povray.advanced-users : HDR compositing? Server Time
31 Oct 2024 19:32:30 EDT (-0400)
  HDR compositing? (Message 1 to 5 of 5)  
From: Thomas de Groot
Subject: HDR compositing?
Date: 25 May 2014 08:00:46
Message: <5381db6e$1@news.povray.org>
Does anyone know how to do HDR compositing in POV-Ray, or something 
giving similar results? I do not mean a hdr output, but something more 
sophisticated than simple averaging of images.

Thomas


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From: Christian Froeschlin
Subject: Re: HDR compositing?
Date: 1 Jul 2014 16:37:47
Message: <53b31c1b$1@news.povray.org>
On 25.05.2014 14:00, Thomas de Groot wrote:

> Does anyone know how to do HDR compositing in POV-Ray, or something
> giving similar results? I do not mean a hdr output, but something more
> sophisticated than simple averaging of images.

A bit late reply but I think you can do the following:

- Treat the different exposures as functions (split into R + G + B)
- Combine these into new functions using "select": use value
   from longer exposure by default, pull values from shorter exposure
   where longer exposure is above some threshold (e.g. 0.9). When using
   value of shorter exposure divide by appropriate factor (depending
   on difference in stops)
- Render combined function pigment with HDR output


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From: Thomas de Groot
Subject: Re: HDR compositing?
Date: 2 Jul 2014 03:08:37
Message: <53b3aff5$1@news.povray.org>
On 1-7-2014 22:37, Christian Froeschlin wrote:
> On 25.05.2014 14:00, Thomas de Groot wrote:
>
>> Does anyone know how to do HDR compositing in POV-Ray, or something
>> giving similar results? I do not mean a hdr output, but something more
>> sophisticated than simple averaging of images.
>
> A bit late reply but I think you can do the following:
>
> - Treat the different exposures as functions (split into R + G + B)
> - Combine these into new functions using "select": use value
>    from longer exposure by default, pull values from shorter exposure
>    where longer exposure is above some threshold (e.g. 0.9). When using
>    value of shorter exposure divide by appropriate factor (depending
>    on difference in stops)
> - Render combined function pigment with HDR output
>
>
Thanks Christian. In fact Clipka suggested what I should have known: 
render in exr and post-process in Ive's IC.

Thomas


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From: Christian Froeschlin
Subject: Re: HDR compositing?
Date: 13 Jul 2014 20:53:33
Message: <53c32a0d$1@news.povray.org>
On 02.07.2014 9:08, Thomas de Groot wrote:

> Thanks Christian. In fact Clipka suggested what I should have known:
> render in exr and post-process in Ive's IC.

ah then I misunderstood your question. I thought you wanted
to composite actual photos (taken with different exposure lengths)
as HDR in POV-Ray :)


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From: Thomas de Groot
Subject: Re: HDR compositing?
Date: 14 Jul 2014 02:47:05
Message: <53c37ce9$1@news.povray.org>
On 14-7-2014 2:53, Christian Froeschlin wrote:
> On 02.07.2014 9:08, Thomas de Groot wrote:
>
>> Thanks Christian. In fact Clipka suggested what I should have known:
>> render in exr and post-process in Ive's IC.
>
> ah then I misunderstood your question. I thought you wanted
> to composite actual photos (taken with different exposure lengths)
> as HDR in POV-Ray :)
>
>
Somehow I wanted to use POV-Ray images as equivalents of actual photos. 
It certainly works but the final hdr quality using the Fusion F1 program 
for instance is less than making an exr image in the first place. 
However, it was an interesting experiment which I may use in other 
occasions.

Thomas


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