Wei Lu wrote in sci.optics:
Yes, like bob posted, what you need is a spectrometer designed for
surface reflectance measurement (380~780nm). I am not familiar with the >products in the market, yet I think it could use an integration sphere
with an opening size to cover a meaningful area, but not too big to
deviate much from the measurement principle, maybe 5~10mm diameter, and
with a space that could hold an apple under the opening.
Thanks for going into further detail.
I really like that my idea is not completely dumb and that there
*are* technical solutions.
A problem will be the price of the tool. I will have to purchase it
privately (then use it for my pleasure).
Then you need the software to calculate the colour of the surface.Some
device may have the feature,
What I saw on the Web came with the software. Second problem: I am
glued to Linux. Similar programs that I have used, ran in the Wine
(Windows-) emulator, but I would have to assure that this is
possible with the new tool.
or you can DIY (in principle, by multiply
the incident spectrum (sun's spectrum AM1.5 could be a reference), the >measured reflectance spectrum, and the 3 response curve of the human
eye,and integrate across 380~780nm). You will get a color coordinate,
which are 3 quantitative value that can be used to compare, reproduce,
or automatic select by machine.
While I comprehend everything that mentions a “reference” .., once I
want to really apply your advice, I might have to come back here and
ask a few more questions… though you have probably already
answered each one.
It should be noted that the result is the colour and brightness
perceived by a "standard" observer (the integration sphere), not the
same as human eyes perceived in normal conditions. So you should not
select an area of the "preferred" colour (in this case green) directly
from the colour space (as in >https://en.wikipedia.org/wiki/File:CIE1931xy_CIERGB.svg), instead, like
in machine learning, you should use the "preferred" apples as samples to
get a "preferred" colour space area, then use it as the selection standard.
Yes. Believe it or not, that is what I do already: I take a standard
apple (“big enough”, about 110g and just about as red/yellow as is needed) and
compare in case of doubt.
;) These are cool followups to my initial post. I have assumed that
I will be slightly swamped but it could be worse.
Cheerio, have a nice week-end, marry X-mas or whatever it is, you
will have these days.
Micheal
--
“When you feel there is an unfair burdon on your shoulders
well – that's just the way it is sometimes” (Winston Groom/Forest Gump)
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