hdrgen and photosphere

Hi Folks -

I'm trying to use hdrgen with a response curve created by photosphere. For the image, I have calibration points measured with a luminance meter, and when I make the hdr with photosphere, I get an accurate luminance measurement, but hdrgen gives me a value that's consistently ~10% higher. This is surprising as (I think) I'm using the same response curve for each process.

Here's my hdrgen command:
hdrgen -o ../01.hdr -r canon_5D.rsp -q 100 -f -g *.JPG

Here's what I put into canon_5D.rsp:
7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

Here's canon_5D.rsp after hdrgen is run:
3 1.49643 -0.979 0.486712 -0.00413976
3 1.44009 -0.884479 0.448854 -0.00446749
3 1.46366 -0.875187 0.414554 -0.00303108

And here's the response curve from Photosphere:
"Canon"|"Canon EOS 5D Mark II"|"v.0"|{7.135383e-03,-3.556814e-02,2.441168e+00,-5.786777e+00,4.462320e+00}|{4.543790e-03,3.363440e-02,1.917460e+00,-4.660105e+00,3.792747e+00}|{3.956902e-03,3.244581e-02,1.827308e+00,-4.505138e+00,3.729707e+00}

Am I missing any hdrgen options, or perhaps making an error in my .rsp file? Thanks in advance for any insights.

Mike

Michael Martinez ~ Associate
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Hi Michael,
> I'm trying to use hdrgen with a response curve created by photosphere.

For the image, I have calibration points measured with a luminance
meter, and when I make the hdr with photosphere, I get an accurate
luminance measurement, but hdrgen gives me a value that's consistently
~10% higher. This is surprising as (I think) I'm using the same response
curve for each process.

Here's my hdrgen command:
hdrgen -o ../01.hdr -r canon_5D.rsp -q 100 -f -g *.JPG

Here's what I put into canon_5D.rsp:
7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

The first number in each line in an RSP file is the order of the polynome. Since it is missing in the RSP above (the one you hand-crafted from the Photosphere response), hdrgen deems it invalid and overwrites it with a new one. Try pre-pending a '6 ' to all three lines. hdrgen should than be happy and use the RSP that you supplied, rather than generate one from scratch.

Here's canon_5D.rsp after hdrgen is run:
3 1.49643 -0.979 0.486712 -0.00413976
3 1.44009 -0.884479 0.448854 -0.00446749
3 1.46366 -0.875187 0.414554 -0.00303108

And here's the response curve from Photosphere:
"Canon"|"Canon EOS 5D Mark
II"|"v.0"|{7.135383e-03,-3.556814e-02,2.441168e+00,-5.786777e+00,4.462320e+00}|{4.543790e-03,3.363440e-02,1.917460e+00,-4.660105e+00,3.792747e+00}|{3.956902e-03,3.244581e-02,1.827308e+00,-4.505138e+00,3.729707e+00}

Am I missing any hdrgen options, or perhaps making an error in my .rsp
file? Thanks in advance for any insights.

More info here:
http://www.jaloxa.eu/webhdr/calibrate.shtml

Cheers

Axel

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

Axel

Hmm - pre-appending with a 6 didn't do the trick.

It seems like hdrgen really wants a 3rd order polynomial (no matter what I put into the .rsp, hdrgen overwrites it as such), and I'm not too sure how to translate the 5 values for the R, G, and B channels generated by Photosphere.

As another data point, the other camera curves in my Photosphere preferences file have a variety of values, either 4, 5 or 6 for each channel, depending on the camera.

As a work around, I can apply a multiplier to the .rsp that hdrgen makes, and that gets me pretty close. But I'd also love to know if there's a more direct way to translate the Photosphere data into hdrgen friendly data.

Thanks all -

Mike

···

On May 13, 2013, at 12:14 PM, Axel Jacobs wrote:

Hi Michael,
> I'm trying to use hdrgen with a response curve created by photosphere.

For the image, I have calibration points measured with a luminance
meter, and when I make the hdr with photosphere, I get an accurate
luminance measurement, but hdrgen gives me a value that's consistently
~10% higher. This is surprising as (I think) I'm using the same response
curve for each process.

Here's my hdrgen command:
hdrgen -o ../01.hdr -r canon_5D.rsp -q 100 -f -g *.JPG

Here's what I put into canon_5D.rsp:
7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

The first number in each line in an RSP file is the order of the polynome. Since it is missing in the RSP above (the one you hand-crafted from the Photosphere response), hdrgen deems it invalid and overwrites it with a new one. Try pre-pending a '6 ' to all three lines. hdrgen should than be happy and use the RSP that you supplied, rather than generate one from scratch.

Here's canon_5D.rsp after hdrgen is run:
3 1.49643 -0.979 0.486712 -0.00413976
3 1.44009 -0.884479 0.448854 -0.00446749
3 1.46366 -0.875187 0.414554 -0.00303108

And here's the response curve from Photosphere:
"Canon"|"Canon EOS 5D Mark
II"|"v.0"|{7.135383e-03,-3.556814e-02,2.441168e+00,-5.786777e+00,4.462320e+00}|{4.543790e-03,3.363440e-02,1.917460e+00,-4.660105e+00,3.792747e+00}|{3.956902e-03,3.244581e-02,1.827308e+00,-4.505138e+00,3.729707e+00}

Am I missing any hdrgen options, or perhaps making an error in my .rsp
file? Thanks in advance for any insights.

More info here:
http://www.jaloxa.eu/webhdr/calibrate.shtml

Cheers

Axel

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

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and strage visual artifacts - see screen shot here.

compared to a screenshot of the photosphere created HDR

···

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

Axel

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

Right, so we are on the right track--hdrgen no longer rejects the RSP.

Next question is: how good is the RSP? Try plotting it. If it is smooth and monotonic, without any kinks in it, it's a good one. Otherwise, try generating it from a different sequence. The 5D is used a lot on WebHDR:
http://www.jaloxa.eu/webhdr/cameras/Canon__Canon_EOS_5D.shtml
How does your RSP compare with the averaged one? Note that there is no quality control, and even 'wonky' ones make it into the average.

Axel

···

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

PS: Two more thoughts:

I think hdrgen copes well with scientific notation, but just to double-check: try converting from scientific notation to straight decimal.

Also, I did notice with some of my won sequences that wood with its grain and large areas of non-grey can be tricky. Just for the calibration, I suggest you choose a grey background.

Axel

···

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

Axel

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

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

The rsp looks good - nice and smooth, which makes sense as Photosphere seems to have no trouble with these values. I also tried straight decimal format, and still no luck...

Very curious...

···

On May 13, 2013, at 1:31 PM, Axel Jacobs wrote:

Right, so we are on the right track--hdrgen no longer rejects the RSP.

Next question is: how good is the RSP? Try plotting it. If it is smooth and monotonic, without any kinks in it, it's a good one. Otherwise, try generating it from a different sequence. The 5D is used a lot on WebHDR:
http://www.jaloxa.eu/webhdr/cameras/Canon__Canon_EOS_5D.shtml
How does your RSP compare with the averaged one? Note that there is no quality control, and even 'wonky' ones make it into the average.

Axel

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

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

As I recall, the order is reverse between Photosphere and hdrgen. If the R response is from your Photosphere file is
7.135383e-03,-3.556814e-02,2.441168e+00,-5.786777e+00,4.462320e+00

it should be a "mirror image" in hdrgen:
4.462320e+00, -5.786777e+00, 2.441168e+00, -3.556814e-02, 7.135383e-03

Mehlika

···

On Mon, 13 May 2013, Michael Martinez wrote:

The rsp looks good - nice and smooth, which makes sense as Photosphere seems to have no trouble with these values. I also tried straight decimal format, and still no luck...

Very curious...

On May 13, 2013, at 1:31 PM, Axel Jacobs wrote:

Right, so we are on the right track--hdrgen no longer rejects the RSP.

Next question is: how good is the RSP? Try plotting it. If it is smooth and monotonic, without any kinks in it, it's a good one. Otherwise, try generating it from a different sequence. The 5D is used a lot on WebHDR:
http://www.jaloxa.eu/webhdr/cameras/Canon__Canon_EOS_5D.shtml
How does your RSP compare with the averaged one? Note that there is no quality control, and even 'wonky' ones make it into the average.

Axel

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

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

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

Ah ha!! That's the trick... Things look great now.

Many thanks, both to Axel and Mehlika.

MM

···

On May 13, 2013, at 3:36 PM, Mehlika Inanici wrote:

As I recall, the order is reverse between Photosphere and hdrgen. If the R response is from your Photosphere file is
7.135383e-03,-3.556814e-02,2.441168e+00,-5.786777e+00,4.462320e+00

it should be a "mirror image" in hdrgen:
4.462320e+00, -5.786777e+00, 2.441168e+00, -3.556814e-02, 7.135383e-03

Mehlika

On Mon, 13 May 2013, Michael Martinez wrote:

The rsp looks good - nice and smooth, which makes sense as Photosphere seems to have no trouble with these values. I also tried straight decimal format, and still no luck...

Very curious...

On May 13, 2013, at 1:31 PM, Axel Jacobs wrote:

Right, so we are on the right track--hdrgen no longer rejects the RSP.

Next question is: how good is the RSP? Try plotting it. If it is smooth and monotonic, without any kinks in it, it's a good one. Otherwise, try generating it from a different sequence. The 5D is used a lot on WebHDR:
http://www.jaloxa.eu/webhdr/cameras/Canon__Canon_EOS_5D.shtml
How does your RSP compare with the averaged one? Note that there is no quality control, and even 'wonky' ones make it into the average.

Axel

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

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

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

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

Hi All,

I am not entirely sure that I remember this correctly, but I once looked at these
camera curves in photosphere for the purpose of plotting them. I seem to recall
that the coefficients are reversed relative to how you might expect them.

It may be worth trying to reverse the order of the coefficients, so for the first of
the three lines this would be:

4 4.462320e+00 -5.786777e+00 2.441168e+00 -3.556814e-02 7.135383e-03

Hope this helps.

Cheers,
Erik

···

On May 13, 2013, at 10:31 PM, Axel Jacobs <[email protected]> wrote:

Right, so we are on the right track--hdrgen no longer rejects the RSP.

Next question is: how good is the RSP? Try plotting it. If it is smooth and monotonic, without any kinks in it, it's a good one. Otherwise, try generating it from a different sequence. The 5D is used a lot on WebHDR:
http://www.jaloxa.eu/webhdr/cameras/Canon__Canon_EOS_5D.shtml
How does your RSP compare with the averaged one? Note that there is no quality control, and even 'wonky' ones make it into the average.

Axel

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

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

Erik's post came in after Mehlika's because he got caught in the moderator trap -- his e-mail was not "on the list."

My apologies for not answering the original post, but I was on a plane or two....

Cheers,
-Greg

···

From: Erik Reinhard <[email protected]>
Date: May 13, 2013 2:24:48 PM PDT

Hi All,

I am not entirely sure that I remember this correctly, but I once looked at these
camera curves in photosphere for the purpose of plotting them. I seem to recall
that the coefficients are reversed relative to how you might expect them.

It may be worth trying to reverse the order of the coefficients, so for the first of
the three lines this would be:

4 4.462320e+00 -5.786777e+00 2.441168e+00 -3.556814e-02 7.135383e-03

Hope this helps.

Cheers,
Erik

On May 13, 2013, at 10:31 PM, Axel Jacobs <[email protected]> wrote:

Right, so we are on the right track--hdrgen no longer rejects the RSP.

Next question is: how good is the RSP? Try plotting it. If it is smooth and monotonic, without any kinks in it, it's a good one. Otherwise, try generating it from a different sequence. The 5D is used a lot on WebHDR:
http://www.jaloxa.eu/webhdr/cameras/Canon__Canon_EOS_5D.shtml
How does your RSP compare with the averaged one? Note that there is no quality control, and even 'wonky' ones make it into the average.

Axel

On 05/13/2013 09:21 PM, Michael Martinez wrote:

Using a 4 in front of the Photosphere numbers like this:

4 7.135383e-03 -3.556814e-02 2.441168e+00 -5.786777e+00 4.462320e+00
4 4.543790e-03 3.363440e-02 1.917460e+00 -4.660105e+00 3.792747e+00
4 3.956902e-03 3.244581e-02 1.827308e+00 -4.505138e+00 3.729707e+00

unfortunately results in a wonky HDR with garbage luminance values and
strage visual artifacts - see screen shot here
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.33%20PM.png>.

compared to a screenshot of the photosphere created HDR
<https://dl.dropboxusercontent.com/u/28677369/Screen%20shot%202013-05-13%20at%201.17.55%20PM.png>

On May 13, 2013, at 1:05 PM, Axel Jacobs wrote:

Oops,

try '4 ', not '6 ' as per my last post.

Embarrassingly yours

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

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