## GovardovskiiNomogram

##### >Psychtoolbox>PsychColorimetricData

T_absorbance = GovardovskiiNomogram(S,lambdaMax)

Compute normalized absorbance according to the

nomogram provided in Victor I. Govardovskii et al., 2000,

Visual Neuroscience, Vol. 17, pp. 509-528.

The polynomial approximation has two bands.

Alpha-band, the major band of A1 pigments is taken from

Equation (1) and equation (2) in wavelength range [350,700] nm

(see page 515 in paper)

Beta-band, the minor band of A1 pigments is taken from

Equation (3) and equation (5a, 5b) in wavelgnth range [350,700] nm

(see page 516 in paper)

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 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.

03/08/2002 ly Wrote it starting from DawisNomogram.

`Psychtoolbox/PsychColorimetricData/GovardovskiiNomogram.m`