Qr: Photoreceptor relative quantum catch
In colourvision: Colour Vision Models

Description Usage Arguments Details Value Author(s) References See Also

von Kries transformation. Photoreceptors are assumed to be adapted to the background. This function is used internally in colour vision models.

1	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 `approx`.
`nm`	A sequence of numeric values specifying where interpolation is to take place. See `approx`.

For the von Kries transformation, first the quantum catches of the observed reflectance and the environmental background are calculated (see Q). Then:

qi = Qi/Qbi

where Qi is the quantum catch arising from the observed object and Qbi 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