[argyllcms] Re: [Possible bug in Spyd2.c] Inconsistant readings from Spyder3

  • From: howdy555@xxxxxxxxx
  • To: Roger <argyllcms@xxxxxxxxxxxxx>
  • Date: Fri, 6 Mar 2009 14:11:05 +0100

> Keep in mind that any relatively inexpensive emissive instrument is going to
> have problems in reading extreme low light, that's the hallmark of
> inexpensive. I was once told by Danny Rich that, what we're asking is for
> the instrument to read practically no light -- very difficult to detect few
> photons reliably. So, personally, anything below 1 cd/m2 I tend to take with
> a grain of salt.

Thank you for your comment Roger!
I was not referring to inaccuracy of the instrument (which is obvious)
but rather to erroneous reading - once in about 10 measurements you
get a result which is plainly wrong. This might be the reason of
getting unsatisfactory results with the calibration (obviously the #1
reason is the cra**y Hyundai N220W LCD monitor I have :) ). Using
original code I get error of about DE=17.... I will not present the
results from mine as I need to test it further (so far the result is
so bad I do not believe a single bit of it: DE=3970 (yes, that is
three thousand nine hundred and seventy) - I suspect that I have made
a mistake at placing the sensor - no monitor in the world is THAT bad

> But thank's for your code modification for the Spyder3.

Careful! It was only a proposal - I can certainly hope someone who
owns a Spyder3 would be able to confirm that the problem really exists

From my first tests, my change improves the accuracy but some more
time is needed to find a suitable multiplyer (I think something like
nframes *= 8 upto nframes *= 16 works well. I tried nframes *= 32 but
the results were no better.

I could really use a little bit more feedback on this - c'mon Spyder3
owners! I know you are lurking here :)

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