Tone mapping for animation

Hi David,

Thus my question: is it possible to explicitly set the exposure used in the tonemapping process with any tool in Radiance?

I'd say combine pfilt with ra_tiff, so that you set a fixed exposure with pfilt -e X and keep that untouched in the later conversion using ra_tiff -e 0. Would that work as expected?

Cheers, Lars.

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

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

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

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi all,

Yeah, it is a little unclear what you want. On the one hand if you want what a camera would do with fixed aperture and shutter speed, Jack's option one is correct. If you want to tonemap, we assume you want something like what we would see at each visual environment, and then jacks option two is the way to go. Phisto is very cool. Yet another one of those tools that make you realize how dense these Radiance images are!

-Rob

···

On Oct 22, 2013, at 8:05 AM, Jack de Valpine <[email protected]> wrote:

Hi David,

I am a little unclear on what you want to accomplish but here are a few thoughts.
time series animation with constant exposure on successive frames - use pfilt -1 -e [constant exposure setting] for each frame
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

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

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

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 <[email protected]>

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 Incorporatedwww.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

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

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 <[email protected] <mailto:[email protected]>>

    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

    _______________________________________________
    Radiance-general mailing list
    [email protected] <mailto:[email protected]>
    http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Hi Jack,

I guess Greg is the only one to answer that question.
However, I guess some tone mapping has to be done as the HDR-JPG format is
backwards compatible and all viewers that read JPGs also read that. So
somehow they need to get get the tonemapped information...

Cheers,
David

···

2013/10/22 Jack de Valpine <[email protected]>

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 Incorporatedwww.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 <[email protected]>

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 Incorporatedwww.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

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Yep, it's a tonemapped jpg that retains (in a lossy way) the HDR info, so you can share these with people sans HDR image viewers and still retain backward compatibility (and enjoy a smaller file size). The paper is here:

http://www.anyhere.com/gward/papers/cic05.pdf

I do not know exactly what operator is used by hdr2jpeg...

- Rob

···

From: David Geisler-Moroder [mailto:[email protected]]
Sent: Tuesday, October 22, 2013 9:50 AM
To: Radiance general discussion
Subject: Re: [Radiance-general] Tone mapping for animation

Hi Jack,
I guess Greg is the only one to answer that question.
However, I guess some tone mapping has to be done as the HDR-JPG format is backwards compatible and all viewers that read JPGs also read that. So somehow they need to get get the tonemapped information...
Cheers,
David

2013/10/22 Jack de Valpine <[email protected]<mailto:[email protected]>>
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<http://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 <[email protected]<mailto:[email protected]>>
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

_______________________________________________

Radiance-general mailing list

[email protected]<mailto:[email protected]>

http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________

Radiance-general mailing list

[email protected]<mailto:[email protected]>

http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]<mailto:[email protected]>
http://www.radiance-online.org/mailman/listinfo/radiance-general

I don't use hdr2jpeg myself, and it isn't distributed with Radiance. Depending on which version you have, it applies either a Reinhard TMO or a variant of the histogram adjustment operator in pcond, but there's no way to tell it to use a specific curve as you can with the pcond -I option Jack mentioned. The latter technique with phisto is what I generally use if I want a sequence exposed the same. And, you can go on using the same histogram for future frames so long as they don't change too much from the range of past frames.

Cheers,
-Greg

···

From: David Geisler-Moroder <[email protected]>
Date: October 22, 2013 8:50:27 AM PDT

Hi Jack,

I guess Greg is the only one to answer that question.
However, I guess some tone mapping has to be done as the HDR-JPG format is backwards compatible and all viewers that read JPGs also read that. So somehow they need to get get the tonemapped information...

Cheers,
David

2013/10/22 Jack de Valpine <[email protected]>
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 <[email protected]>
Hi David,

I am a little unclear on what you want to accomplish but here are a few thoughts.
time series animation with constant exposure on successive frames - use pfilt -1 -e [constant exposure setting] for each frame
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

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

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Perfect, thanks for the clarification Greg!

Another short note:
I just found out that one thing that also made my life hard with getting
the scene constantly exposed was the inclusion of a time stamp in the image
with psign before sending the image through pcond... stupid error on my
side as this introduces virtual luminances that are not in the scene.

···

2013/10/22 Greg Ward <[email protected]>

I don't use hdr2jpeg myself, and it isn't distributed with Radiance.
Depending on which version you have, it applies either a Reinhard TMO or a
variant of the histogram adjustment operator in pcond, but there's no way
to tell it to use a specific curve as you can with the pcond -I option Jack
mentioned. The latter technique with phisto is what I generally use if I
want a sequence exposed the same. And, you can go on using the same
histogram for future frames so long as they don't change too much from the
range of past frames.

Cheers,
-Greg

*From: *David Geisler-Moroder <[email protected]>

*Date: *October 22, 2013 8:50:27 AM PDT

*
*

Hi Jack,

I guess Greg is the only one to answer that question.
However, I guess some tone mapping has to be done as the HDR-JPG format is
backwards compatible and all viewers that read JPGs also read that. So
somehow they need to get get the tonemapped information...

Cheers,
David

2013/10/22 Jack de Valpine <[email protected]>

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 Incorporatedwww.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 <[email protected]>

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 Incorporatedwww.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

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing [email protected]://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

Indeed. The usual way of getting a label into an image is using pcompos, which strips the image of exposure information that pcond needs to do its job. Since the output of pcond in most cases has lost its useful luminance information, it works well to apply the label at that point and/or convert to some non-HDR image type via ra_whatever.

Cheers,
-Greg

···

From: David Geisler-Moroder <[email protected]>
Date: October 22, 2013 9:45:12 AM PDT

Perfect, thanks for the clarification Greg!

Another short note:
I just found out that one thing that also made my life hard with getting the scene constantly exposed was the inclusion of a time stamp in the image with psign before sending the image through pcond... stupid error on my side as this introduces virtual luminances that are not in the scene.

2013/10/22 Greg Ward <[email protected]>
I don't use hdr2jpeg myself, and it isn't distributed with Radiance. Depending on which version you have, it applies either a Reinhard TMO or a variant of the histogram adjustment operator in pcond, but there's no way to tell it to use a specific curve as you can with the pcond -I option Jack mentioned. The latter technique with phisto is what I generally use if I want a sequence exposed the same. And, you can go on using the same histogram for future frames so long as they don't change too much from the range of past frames.

Cheers,
-Greg