[T_quantalAbsorptionsNormalized,T_quantalAbsorptions,T_quantalIsomerizations,adjIndDiffParams] = ComputeRawConeFundamentals(params,staticParams)
Function to compute normalized cone quantal sensitivities from underlying
pieces and parameters.
Note that this routine returns quantal sensitivities. You may want
energy sensitivities. In that case, use EnergyToQuanta to convert
T_energy = EnergyToQuanta(S,T_quantal’)’
and then renormalize. (You call EnergyToQuanta because you’re converting
sensitivities, which go the opposite direction from spectra.)
The routine also returns two types of quantal sensitivity functions. The
first gives the probability that a photon will be absorbed. These are
returned in variable T_quantalAbsorptionsNormalized and
T_quantalAbsorptions, with the first being normalized. The second is the
probability that the photon will cause a photopigment isomerization. This
is returned in T_quantalIsomerizations.
It is T_quantalIsomerizations that you want to use to compute
isomerization rates from retinal illuminance. See note at the end of
function FillInPhotoreceptors for some information about conventions. In
particular, this routine takes pre-retinal absorption into account in its
computation of probability of absorptions and isomerizations, so that the
relevant retinal illuminance is one computed without accounting for those
factors. This routine does not account for light attenuation due to the
pupil, however. The only use of pupil size here is becuase of its slight
effect on lens density as accounted for in the CIE standard. Nor does it
account for the collecting area of a photoreceptor, for cones the inner
In the passed params structure, you can either pass the lambdaMax values
for the photopigment, in which case the absorbance is computed from the
specified nomogram, or you can pass the absorbance values directly in
T_xxx format. A typical choice in this case would be
10.^T_log10coneabsorbance_ss for the Stockman-Sharpe/CIE estimates.
The typical use of this function is to be called by
ComputeCIEConeFundamentals, which sets up the passed structures acording
to the CIE standard. This routine, however, could in principle be used
with a wide variety of choices of the component pieces.
The other place this function is used is in attempts to fit a set of cone
fundamentals by doing parameter search over the pieces. It is this
second use that led to the parameters being split over two separate
structures, one that is held static during the fit and the other which
contains the parameters that could be searched over by a calling routine.
For examples, see:
Looking around today (8/10/13), I (DHB) don’t see any examples where this
routine is called directly. Rather, it is a subfunction called by
ComputeCIEConeFundamentals. The search routines above use
ComputeCIEConeFundamentals, and only search over lambdaMax values. I
think I wrote this with the thought that I might one day search over more
parameters, but lost motivation to carry it throught.
The computations done here are very similar to those done in routine
FillInPhotoreceptors. I (DHB) think that I forgot about what
FillInPhotoreceptors could do when I wrote this, which has led to some
redundancy. FillInPhotoreceptors returns a field called
effectiveAbsorptance, which are the actual quantal efficiencies (not
normalized) referred to the cornea. FillInPhotoceptors also computes a
field isomerizationAbsorptance, which takes the quantal efficiency of
isomerizations (probability of an isomerization given an absorption into
It would probably be clever to unify the two sets of routines a little
more, but we may never get to it. The routine ComputeCIEConeFundamentals
does contain a check that this routine and what is returned by
FillInPhotoreceptors agree with each other, for cases where the
See ComputeCIEConeFundamentals for the breakdown of how the Asano et al.
(2016) individual differences model is specified in params.indDiffParams.
See ComputeCIEConeFundamentals for documentation of the adjIndDiffParams
8/12/11 dhb Starting to make this actually work.
8/14/11 dhb Change name, expand comments.
8/10/13 dhb Expand comments. Return unscaled quantal efficiencies too.
2/26/16 dhb, ms Add in Asano et al. (2016) individual observer adjustments
3/30/17 ms Added output argument returning adjusted ind differences
6/4/18 ms Included absorbance spectrum into adjusted ind diff output arg