| Qr {colourvision} | R Documentation |
von Kries transformation. Photoreceptors are assumed to be adapted to the background. This function is used internally in colour vision models.
Qr(R, I, Rb, C, interpolate, nm)
R |
Reflectance of observed object. A data frame with two columns only: first column corresponding to wavelength values and second column with reflectance values. |
I |
Irradiance spectrum. A data frame with two columns only: first column corresponding to wavelength values and second column with irradiance values. Irradiance values must be in quantum flux units. |
Rb |
Background reflectance. A data frame with two columns only: first column corresponding to wavelength values and second column with reflectance values. Photoreceptors are assumed to be adapted to the background reflectance. |
C |
Photoreceptor sensitivity curve. A data frame with two columns only: first column corresponding to wavelength values and second column with photoreceptor absorbance values. |
interpolate |
Whether data files should be interpolated before further calculations. See |
nm |
A sequence of numeric values specifying where interpolation is to take place. See |
For the von Kries transformation, first the quantum catches of the observed reflectance and the environmental background are calculated (see Q). Then:
qi = \frac{Q_i}{Q_{bi}}
where Q_i is the quantum catch arising from the observed object and Q_{bi} is the quantum catch from the background, for each one of the photoreceptor types (i).
Photoreceptor relative quantum catch.
Felipe M. Gawryszewski f.gawry@gmail.com
Backhaus, W. 1991. Color opponent coding in the visual system of the honeybee. Vision Res 31:1381-1397.
Chittka, L. 1992. The colour hexagon: a chromaticity diagram based on photoreceptor excitations as a generalized representation of colour opponency. J Comp Physiol A 170:533-543.
Endler, J. A., and P. Mielke. 2005. Comparing entire colour patterns as birds see them. Biol J Linn Soc 86:405-431.
Vorobyev, M., and D. Osorio. 1998. Receptor noise as a determinant of colour thresholds. Proceedings of the Royal Society B 265:351-358.
CTTKmodel, EMmodel, RNLmodel, RNLthres, GENmodel