[sudo-discuss] Spectral Response Curves

[Steve Berl]

Another thought. How about one of those monitor calibration devices like
the Datacolor Spider. I've got one you could borrow. Here's an article
about how to use it with Linux.
http://www.gdargaud.net/Hack/LinuxSpyder.html

They use software called dispcal http://dispcalgui.hoech.net/

I'd guess that if you dig into the source for that you can find code to
control and read color data from the Spyder.

-steve


On Tue, Nov 12, 2013 at 9:59 AM, Steve Berl <steveberl at gmail.com> wrote:

> I will check with folks at the East Bay Astronomical Society up at Chabot
> Space & Science Center. There is some amount of spectroscopy equipment
> around up there. Though much of it is very old, and intended for
> astronomical observations (attached to a telescope), something might be
> useful, and there might be someone who is interested in helping out.
>
> -steve
>
>
> On Tue, Nov 12, 2013 at 12:42 AM, Marc Juul <juul at labitat.dk> wrote:
>
>> You might want to repeat the question on the Counter Culture Labs mailing
>> list:
>>
>>   https://counterculturelabs.org/
>>
>>
>> On Mon, Nov 11, 2013 at 2:47 PM, Peter Kwangjun Suk <
>> peter.kwangjun.suk at gmail.com> wrote:
>>
>>> (Also posted to Noisebridge. Skip if you are experiencing deja-vu.)
>>>
>>> Hello,
>>>
>>> Right now, I'm doing research for a specialized app to let consumers
>>> validate products that can be used to treat insomnia. Specifically, I'm
>>> working on a smartphone app that can act like a light detector for light in
>>> a narrow band around 470 nanometers. This is the frequency that has been
>>> shown to suppress melatonin secretion by the pineal gland.
>>>
>>> There are specialty products for avoiding late night 470 nanometer light
>>> exposure (light bulbs, screen overlays, glasses) but these are often very
>>> overpriced, and there is no convenient way to validate them. There are also
>>> "ordinary" products that serve the same purpose, but there is no good way
>>> for people to accurately test them. Currently, people can use a CD or DVD
>>> as an ad-hoc diffraction grating and look at the resulting spectrum, but
>>> even this isn't quite good enough. I've bought a narrow bandpass filter for
>>> 470nm light, and even products that have a spectrum that "looks good" (very
>>> little blue) can have hot-spots that leak large amounts of 470nm light, and
>>> it doesn't take much to suppress melatonin. (As low as 0.5 lux for
>>> prolonged exposures.)
>>>
>>> Looking generally at spectral response curves for digital cameras, it
>>> should be possible to "synthesize" a narrow band detector by taking the
>>> blue channel response and subtracting the red channel value.
>>>
>>>
>>> http://www.maxmax.com/images/Cameras/Technical/NikonD200_SpectralResponse.jpg
>>>
>>> This should effectively produce a "synthetic" instrument that has a
>>> spectral response curve that would be the camera's blue response, minus its
>>> red response. Even more helpful, the user should be able to view a
>>> synthesized narrowband image of the product, to be able to spot leaks and
>>> hot spots.
>>>
>>> What I need: I would like help in scientifically measuring the spectral
>>> response curve of the "synthetic instrument." I already have a (tiny) 470nm
>>> filter from Thorlabs, and I'm already aware of Public Lab's DIY
>>> spectroscope. I would like to use more accurate equipment, however. It is
>>> important that I can provide accurate information about the performance of
>>> the app and use rigorous procedures for measurement so that users know they
>>> can rely on the instrument.
>>>
>>> Does anyone have the expertise and access to equipment to help me out?
>>>
>>> --SCZ
>>>
>>>
>>>
>>> --
>>> There's neither heaven nor hell,
>>> save what we grant ourselves.
>>> There's neither fairness nor justice,
>>> save what we grant each other.
>>>
>>> _______________________________________________
>>> sudo-discuss mailing list
>>> sudo-discuss at lists.sudoroom.org
>>> http://lists.sudoroom.org/listinfo/sudo-discuss
>>>
>>>
>>
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>>
>
>
> --
> -steve
>



-- 
-steve
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