[argyllcms] Re: About Hi-Res spectral mode
- From: Gerhard Fuernkranz <nospam456@xxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Mon, 03 Oct 2011 18:12:45 +0200
Btw, if you want to assess the noise, you could measure the light source say
100 times, and compute the standard deviation of the 100 readings at each
spectral band, and/or plot the 100 curves on top of each other in order to
visualize the same (Make sure though, that the light source is stable during
the time of the measurements, otherwise you might mis-interpret a drift of the
light source as noise, unless you'd estimate and compensate the drift).
And you can average the 100 readings. Note that averaging 100 independent
readings is supposed reduce random noise by a factor of sqrt(100) = 10. So
plotting the average of the 100 readings should result in a smoother curve,
with less noise. Any deviation/anomaly you observe in a single reading, which
does not decrease by a factor of at least 5 in the average of the 100 readings,
is with ~95% probability NOT caused by random noise, but likely a systematic
component (i.e. either it is actually present in the measured spectrum, or it's
a systematic measurement error).
Best Regards
Gerhard
Am 03.10.2011 13:01, schrieb Gerhard Fürnkranz:
Well, the sensor's sensitivity is typically bell-shaped, so the S/N ratio is
certainly better at green wavelengths, while it can be significantly worse at
the blue and red end.
"János, Tóth F."<janos666@xxxxxxxxxx> schrieb:
I noticed it when I made my previous charts that the wavelength interval is
extended in HiRes mode and the curves seem "noisy" in that extra range.
[...]
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