[Radiance-general] calculating global illuminance from an HDR image of an angular, fish-eye view

[Greg Ward]

Hi Chris,

It took me a while to find the thread.  Search seems to be broken on radiance-online.  Very annoying....

	http://www.radiance-online.org/pipermail/radiance-general/2009-February/005780.html

Cheers,
-Greg

> From: Humann Chris <chris at coolshadow.com>
> Date: July 11, 2012 2:59:26 PM PDT
> 
> Dear group,
> 
> I recall seeing a 'pcomb' routine listed here for calculating the global illuminance of a HDR scene calculated with  an angular fish-eye view (-vta) but now can't seem to find it.  Does anyone have this that they would be willing to share?
> 
> As always, thanks and best regards.
> 
> Chris
> 
> Christian Humann ~ Associate
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> 
> On Sep 23, 2010, at 10:53 AM, Lars O. Grobe wrote:
> 
>> Hi,
>> 
>> There are cheap photospectrometers available starting at $1000, but if you want to measure total luminous flux or diffuse reflectance, you will need an integrating sphere. The sphere is the expensive component of such a setup.
>> 
>> Cheers, Lars.
>> 
>> --
>> Dipl.-Ing. Architect Lars O. Grobe
>> 
>> On Sep 23, 2010, at 19:44, "Randolph M. Fritz" <RFritz at lbl.gov> wrote:
>> 
>>> Christoph,
>>> 
>>> Imaging technology is awfully cheap these days. I think something could be improvised with standard filters and a moderately-priced camera, but it would take some expertise to design, fabricate, and calibrate.  Design expertise, of course, we have on this list, fabrication and calibration, not so much (at least, I don't think we do.)  Have you thought about wandering over to your local physics department & asking for help?  Or perhaps to MIT?  It might make a good student project.
>>> 
>>> Randolph
>>> 
>>> 
>>> On 2010-09-23 10:05:56 -0700, Reinhart, Christoph said:
>>> 
>>>> Dear all:
>>>> 
>>>> I am looking for an affordable (<$3000) set of devices that can measure the spectral power distribution of light sources in the visible range as well as wavelength dependant surface reflectances. Does something like this exist? At the NRC we had a $10,000 Minolta spectrometer that measured wavelength dependant diffuse reflectances as well as overall specular reflectance. Are there any more affordable devices? What are you using for light sources?
>>>> 
>>>> Christoph
>>>> 
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