DawisNomogram

Psychtoolbox › PsychColorimetricData

[T_absorbance] = DawisNomogram(S,lambdaMax)

Compute normalized absorbance according to the
nomogram provided in Dawis, 1981, Vision Research,
Vol. 21, pp. 1427-1430.

T_absorbance contains the absorbance.
This is specified according to the CVRL web page
definition absorbance = log(I_incident/I_transmitted),
so the numbers are all positive. The peak is normalized
to one.

For low density, the absorbance has the same shape as
the spectral senstivity.

The nomogram is shifted along the wavelength axis
using a multiplicative rather than additive procedure.

The result is in quantal units, in the sense that to compute
absorbtions you want to incident spectra in quanta.
To get sensitivity in energy units, apply EnergyToQuanta().

Argument lambdaMax may be a column vector of wavelengths.

10/30/97 dhb Wrote it.
07/01/03 dhb Add computation of T_absorbance.