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<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>I’m not sure what you mean by the “radiance scale
factor”. Are you trying to compute the cameras’ response curves? As
for your second question, you won’t be able to calculate radiance from a
single exposure, even if all the details about that exposure are known. The
process you are describing requires a high dynamic range (HDR) image, which is comprised
of multiple exposures. The typical minimum is three exposures separated by 2
f-stops each, but ideally the longest exposure should have zero black pixels
and the shortest have no white pixels. This ideal is only necessary to capture
scenes of extreme dynamic range, however. <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Radiance-online.org also hosts an hdr mailing list which is
definitely worth subscribing to:<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><a
href="http://www.radiance-online.org/mailman/listinfo/hdri">http://www.radiance-online.org/mailman/listinfo/hdri</a><span
style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Robert Guglielmetti IES, LEED AP<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Building Energy Efficiency Engineer</span><span
style='font-size:9.0pt;font-family:"Arial","sans-serif";color:#1F497D'> <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>National Renewable Energy Laboratory (NREL)<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>1617 Cole Blvd, MS-5202<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>Golden, CO 80401<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>robert.guglielmetti@nrel.gov<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:9.0pt;font-family:"Arial","sans-serif";
color:#1F497D'>303.275.4319<o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> radiance-general-bounces@radiance-online.org
[mailto:radiance-general-bounces@radiance-online.org] <b>On Behalf Of </b>Brajesh
Lal<br>
<b>Sent:</b> Wednesday, July 01, 2009 7:55 AM<br>
<b>To:</b> radiance-general@radiance-online.org<br>
<b>Subject:</b> [Radiance-general] Radiance<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal>Hi All,<o:p></o:p></p>
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<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>I have taken images of same scene from two different camera
at same time and same day. How to find the radiance scale factor between the
two cameras.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><o:p> </o:p></p>
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<div>
<p class=MsoNormal>I will be grateful if somebody can explain me mathematical
relation to compute the radiance of a point in the scene.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>if the pixel value of the point and cameras ISO value,
F-stop, Shutter Speed are known<o:p></o:p></p>
</div>
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<p class=MsoNormal><o:p> </o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal>Best Regards, <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal>Brajesh Lal<o:p></o:p></p>
<div>
<p class=MsoNormal><o:p> </o:p></p>
</div>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
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