spectral measurements

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

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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--
Randolph

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" <[email protected]> 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

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

--
Randolph

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

Well, there's always PAB. If he can design, fabricate, and calibrate goniophotometers, I'm sure he'd be up to spectral power measurements. ;^)
(Is PAB still on this list?)

Chris, we missed you at the workshop, btw.

Regards,

--Roland

···

On Thu, 23 Sep 2010 19:44:21 +0200, Randolph M. Fritz <[email protected]> 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.

--
Dr. Roland Schregle
System Administrator
Institute for Applied Mathematics
Bonn University
Endenicher Allee 60
53115 Bonn
Germany

Any specific recommendations to look for in this range, or explanation why the Minolta would be any better?

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.

···

-----Original Message-----
From: Lars O. Grobe

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?

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