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function T = LambNomogram(S,lambdaMax)
% T = LambNomogram(S,lambdaMax)
%
% Compute spectral sensitivities according to the
% nomogram provided in Lamb, 1995, Vision Research,
% Vol. 35, pp. 3083-3091, equation 2'.
%
% The result is in quantal units, in the sense that to compute
% absorptions you want to incident spectra in quanta.
% To get sensitivity in energy units, apply EnergyToQuanta().
%
% Argument lambdaMax may be a column vector of wavelengths.
%
% 8/20/98 dhb Wrote it.
% These are the coefficients for Equation 2.
a = 70; b = 28.5; c = -14.1;
A = 0.880; B = 0.924; C = 1.104; D = 0.655;
% Get wls argument.
wls = MakeItWls(S);
[nWls,nil] = size(wls);
[nT,nil] = size(lambdaMax);
T = zeros(nT,nWls);
for i = 1:nT
theMax = lambdaMax(i);
wlarg = theMax ./ wls';
T(i,:) = 1 ./ ( ...
exp( a*(A-wlarg) ) + ...
exp( b*(B-wlarg) ) + ...
exp( c*(C-wlarg) ) + ...
D ...
);
T(i,:) = T(i,:)/max(T(i,:));
end
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