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