ReE: I can't get even similar irradiancevalues from a lamp.

Also, I'm curious how you'd use LAMPCOLOR for a UV-lamp? Obviously the efficacy would not be the usual 179?

YC Huang

···

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Message: 3
Date: Sun, 15 Mar 2009 09:54:28 -0700
From: Greg Ward <[email protected]>
Subject: Re: [Radiance-general] I can't get even similar irradiance
values from a lamp.
To: Radiance general discussion <[email protected]>
Message-ID: <[email protected]>
Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed

How did you measure the UV reflectance of the surfaces of your box?
Most paints drop off dramatically from the visible spectrum to UV.
White paints may re-emit UV as visible so they appear "whiter" under
daylight illumination. You really need to know the behavior of your
paint with respect to ultraviolet wavelengths to do this correctly.

-Greg

> From: Minki Sung <[email protected]>
> Date: March 14, 2009 10:52:03 PM PDT
>
> Dear Radiance users,
>
> I'm writing here for third time and I always sorry for just asking.
> I'm modeling a small box has a several bared cylindrical
> fluorescent lamps (actually UV lamps) inside and want to know the
> irradiance level on the surfaces of the box. The cylindrical lamps
> has 32mm in diameter and 540mm in length and The radiance of 44W/sr/
> m2 calculated with the UV output of the lamps (7.5W) was applied to
> the lamps. Before calculating the small box model I checked
> irradiance values with an experiment measuring UV intensity at the
> distance of 1 m and compared that with the same simple RADIANCE
> calculation and the result was reasonable. However, the calculation
> results are higher than those of experiments by 2~4 times with the
> small box model. The small box is not simple but not so
> complicated. I have modeled the lamp both as a cylinder and 72
> polygons but there were not so much changes. Only one channel was
> used to calculate irradiances of UV from modeling to issuing
> results and only diffused reflections were assumed. Geometric
> errors or abnormal radiance distributions of lamps could be assumed
> to cause the discrepancy, but 2~5 times are too large
> Here is my rtrace options.
>
> cat pts_sensor.pts | rtrace -I -oov -ar 128 -ad 512 -as 256 -ab 2 -
> ds 0.02 uv.oct > uv.dat
>
> It would be appreciated if anyone give me advice.
>
>
> Sung

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