C
Chris Carlen
- Jan 1, 1970
- 0
Hi:
Don Klipstein made a comment in my recent post to sci.engr.lighting
about "Laser TV" that in 1988 the photopic luminous efficiency function
was changed.
I haven't read about this in my text: DeCusatis, Casimir "Handbook of
Applied Photometry" 1998; nor at Wiki:
http://en.wikipedia.org/wiki/Luminosity_function
http://en.wikipedia.org/wiki/CIE_1931_color_space
However, Wiki mentions the improvements to V(lambda) made by
Judd-Vos in 1978 (perhaps this is what Don was thinking of) and
Sharpe, Stockman, Jagla & Jägle in 2005.
A lot of data on the increasingly large number of functions is available
here: http://cvrl.ioo.ucl.ac.uk/
It is my interest to clarify which functions to use for what purpose.
It would seem one first has to decide if they wish to compute luminosity
which is perceptually valid or luminosity which is standardized for
comparison to other values. In the former case, the newer modified
functions might be preferable. In the latter case, the official 1931
function might be best.
In comparing luminous output from different sources, it is merely
necessary to use the same computation for all sources. It is my
understanding that the 1931 functions are the most standard data sets
used for this work, right?
However to design systems such as laser TV or CRTs/projectors/LCDs based
on combining color primaries to produce certain color gamuts and
brightness levels, one might get more perceptually valid results using
the modified functions, right?
Trouble is, while there are new modified photopic luminous efficiency
functions, there don't appear to be corresponding new color matching
functions for computing color coordinates.
Is it valid to use the modified V_M(lambda) (CIE 1978, Vos modified) for
instance in place of the y_bar color matching function? In the 1931
system it was the case that y_bar = V(lambda) but in the modified sets
this is no longer the case.
Confusing.
Thanks for comments.
--
Good day!
________________________________________
Christopher R. Carlen
Principal Laser&Electronics Technologist
Sandia National Laboratories CA USA
[email protected]
NOTE, delete texts: "RemoveThis" and
"BOGUS" from email address to reply.
Don Klipstein made a comment in my recent post to sci.engr.lighting
about "Laser TV" that in 1988 the photopic luminous efficiency function
was changed.
I haven't read about this in my text: DeCusatis, Casimir "Handbook of
Applied Photometry" 1998; nor at Wiki:
http://en.wikipedia.org/wiki/Luminosity_function
http://en.wikipedia.org/wiki/CIE_1931_color_space
However, Wiki mentions the improvements to V(lambda) made by
Judd-Vos in 1978 (perhaps this is what Don was thinking of) and
Sharpe, Stockman, Jagla & Jägle in 2005.
A lot of data on the increasingly large number of functions is available
here: http://cvrl.ioo.ucl.ac.uk/
It is my interest to clarify which functions to use for what purpose.
It would seem one first has to decide if they wish to compute luminosity
which is perceptually valid or luminosity which is standardized for
comparison to other values. In the former case, the newer modified
functions might be preferable. In the latter case, the official 1931
function might be best.
In comparing luminous output from different sources, it is merely
necessary to use the same computation for all sources. It is my
understanding that the 1931 functions are the most standard data sets
used for this work, right?
However to design systems such as laser TV or CRTs/projectors/LCDs based
on combining color primaries to produce certain color gamuts and
brightness levels, one might get more perceptually valid results using
the modified functions, right?
Trouble is, while there are new modified photopic luminous efficiency
functions, there don't appear to be corresponding new color matching
functions for computing color coordinates.
Is it valid to use the modified V_M(lambda) (CIE 1978, Vos modified) for
instance in place of the y_bar color matching function? In the 1931
system it was the case that y_bar = V(lambda) but in the modified sets
this is no longer the case.
Confusing.
Thanks for comments.
--
Good day!
________________________________________
Christopher R. Carlen
Principal Laser&Electronics Technologist
Sandia National Laboratories CA USA
[email protected]
NOTE, delete texts: "RemoveThis" and
"BOGUS" from email address to reply.
