[Radiance-general] Tone mapping for animation

[Jack de Valpine]

Hi David,

Great, glad it helped!

I have not used the hdr2jpeg utility so I am not really sure what it 
does. My impression is that it converts to a jpeg that contains hdr 
information. I do not think that it does tone mapping though. Perhaps 
others can weigh in...

Best,

-Jack

-- 
Jack de Valpine
President

Visarc Incorporated
www.visarc.com

channeling technology for superior design and construction

On 10/22/2013 11:14 AM, David Geisler-Moroder wrote:
> Hi Jack, hi Lars,
>
> thanks a lot for the quick response!
> Jack, your second hint exactly did what I was looking for. I tried to 
> use pcond first, but didn't think of the possibility to use a histogram...
>
> Sorry, if my description was somehow cryptic, but you exactly found 
> what I wanted...
>
> Just for information: the pfilt exposure corrections do not help in my 
> case because the tone-mapping that is done in the HDR2LDR conversion 
> (with hdr2jpeg / ra_tiff or similar) does the tone mapping for each 
> single frame independent from the other images. (But maybe I just got 
> something terribly wrong here...!?)
>
> Thanks!
> David
>
>
>
> 2013/10/22 Jack de Valpine <jedev at visarc.com <mailto:jedev at visarc.com>>
>
>     Hi David,
>
>     I am a little unclear on what you want to accomplish but here are
>     a few thoughts.
>
>      1. time series animation with constant exposure on successive
>         frames - use pfilt -1 -e [constant exposure setting] for each
>         frame
>      2. time series animation with tone mapping function on successive
>         frames - use pcond and phisto, phisto will compute a histogram
>         across a series of frames pcond can then use the results from
>         phisto to tone map the frames according to selected tone
>         mapping operator, there is a an example in the man page for pcond
>
>     I think that maybe where I am confused by your description is that
>     since Radiance output is already HDR, setting exposure is really a
>     post process. I think that what you are looking for is the second
>     option that I describe above.
>
>     Not sure if this answers your questions, but perhaps gives you
>     some things to look into.
>
>     Best,
>
>     -Jack
>
>     -- 
>     Jack de Valpine
>     President
>
>     Visarc Incorporated
>     www.visarc.com  <http://www.visarc.com>
>
>     channeling technology for superior design and construction
>
>     On 10/22/2013 9:45 AM, David Geisler-Moroder wrote:
>>     Hi all,
>>
>>     I have a question concerning the tone mapping procedures
>>     implemented in the Radiance tools.
>>     For an animation of a full day I would like to get something
>>     similar that a camera would do that just takes a picture every 5
>>     minutes with the same settings (exposure time and aperture).
>>     Rendering the images for every 5 minutes is not a problem,
>>     however, I stuck when trying to convert the HDRs to some
>>     tonemapped images. As far as I got it, In ra_jpeg/hdr2jpeg no
>>     exposure can be given at all, in ra_tiff/ra_bmp only relative
>>     exposures can be applied.
>>
>>     Thus my question: is it possible to explicitly set the exposure
>>     used in the tonemapping process with any tool in Radiance?
>>
>>     Thanks in advance!
>>     David
>>
>>
>>
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>
>
>
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