Thread: Neo900 - finally a successor of N900
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Oblomow is offline Oblomow
2016-01-09 , 16:02
Posts: 72 | Thanked: 184 times | Joined on Apr 2011 @ Germany
#2760
Originally Posted by wpwrak View Post
Of course, two parameters are still a very course approximation of the actual spectrum. But you'd probably need serious lab equipment to determine that. (A comparison between two LEDs would be easier, though, since any systematic errors of the test setup would affect both measurements in the same way. Joerg suggested using a prism. You'd still need a proper lab setup, though, if only to make sure the geometry doesn't change between tests.)

- Werner
There's a nice instruction on how making a spectrometer out of cardbox and a DVD-R as a diffraction grating:
https://publiclab.org/sites/default/...ni-spec3.8.pdf
Using a good camera, it seems possible to get surprisingly good results from this:
https://publiclab.org/notes/cfastie/...ometer-testing

So, if you're a bit into that stuff, it could be fun to build one (I feel a bit tempted to do this myself now ).

But the most pragmatic solution probably is this: get a colorchecker chart, take a raw image on the n900 with fcamera using LED illumination, compare using a standard white balance setting, pick the LED closest to the original one. Just from the spectrum, the effects of different LEDs could be a bit hard to predict, because of the color filter array on the sensor and its transmission function.
 

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