Re: "Full-spectrum" article on Wikipedia

"Ioannis" <morpheus@xxxxxxxxxxxx> wrote in message
news:1180995005.324031@xxxxxxxxxxx
[snip]


http://www.lrc.rpi.edu/programs/nlpip/publicationdetails.asp?ID=887&type=2

Many thanks, Terry. Sounds like an interesting approach. I will see
if
I can implement it in Maple and add it to the Engineering document,
so
as to have an FSI objective as well.

First, I have to figure exactly how the FSI is calculated and what
they mean exactly by "a reference equal energy source" and I quote:

"In selecting an ideal light source as a reference, an equal energy
spectrum becomes the logical choice for two main reasons. First, the
SPD of an equal energy spectrum is, indeed, "full" across the entire
visible spectrum and, second, an equal energy spectrum is neutral
with
regard to any prejudicial associations, positive or negative, with
"natural" light sources. Moreover, there are several electric and
natural light sources that have SPDs approximating an equal energy
spectrum, so choosing an equal energy spectrum as the reference
full-spectrum source is not entirely abstract or irrelevant.

Formally then, the proposed reference full-spectrum light source is
an
ideal light source with equal energy across the visible region of
the
spectrum, from 380 to 730 nm, inclusive. A new metric, called
full-spectrum index (FSI), based on this proposed reference..."

So, do you or anyone else have any idea what the spectrum of this
"reference equal energy source" should look like? Looks to me like I
should load a full spectrum from 380-700nm with all bin intensities
equal to 100, unless someone has a better interpretation. What say
ye?

Based on my understanding of what they write, I *think* what they mean
then for the FSI calculation is the following:

FSI = sum((100-i_k)^2,k=380..730)/(730-380) =

[(100-i_380)^2 + (100-i_381)^2 + ... + (100-i_730)^2]/350

where i_k is the spectrum intensity at wavelength k of the measured
source (with both sources maxima being at 100). That looks indeed like
a mathematical metric.

Wonderful :-)

Will notify the group when all calculations are redone. Terry goes in
the credits and so does this article.

Terry McGowan
--
I.N. Galidakis --- http://ioannis.virtualcomposer2000.com/
----------------------------------------------------------
"There's ALWAYS a mistake somewhere"

.

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