0.1 nm steps
1 nm steps
5 nm steps
| Units | 0.1 nm steps |
1 nm steps |
5 nm steps |
| Quantal (log) |
|
|
|
| Energy (log) |
|
|
|
| Energy (linear) |
|
|
|
Data keyColumns
Quantal
Logarithmic
Energy
Logarithmic
Linear
Notes 10° cone spectral sensitivities: log L10(l) or log
, log M10(l) or log
and log S10(l) or log
at 0.1, 1 or 5 nm
steps. The 0.1 and 1 nm functions were obtained by the interpolation of the 5 nm functions
using a cubic spline. The functions are normalized to peak at unity at the nearest
0.1 nm step.
The cone spectral sensitivities are defined as
linear combinations of the Stiles and Burch (1959) 10-deg
CMFs, 
, 
and 
.
Their derivation requires a knowledge of the five unknowns, 
, 
, 
, 
and 
, in the
following equations:
Stockman, Sharpe & Fach (1999) and Stockman and Sharpe (2000)
estimated the five unknowns from L- and M-cone spectral sensitivity measurements in single-gene red-green dichromats, S-cone spectral
sensitivity measurements in blue cone monochromats
and normals, and from existing color matching data. The estimates are 
=0.010600 for S; 
=0.168926
and 
=8.265895
for M and 
=2.846201 and 
=11.092490
for L. The values of 
, 
, and 
, the absolute values of which are unknown, were chosen so that the
three functions peak at one.
For further details, see Stockman, Sharpe & Fach (1999) and Stockman & Sharpe (2000). Stockman, Sharpe & Fach (1999) were unable to measure S-cone spectral sensitivity data after 615 nm, after which S(l) is so small that it can reasonably, for most purposes, be set to zero.
ReferencesStiles, W. S. & Burch, J. M. (1959). NPL colour-matching investigation: Final report. Optica Acta, 6, 1-26.
Stockman, A., Sharpe, L. T., & Fach, C. C. (1999). The spectral sensitivity of the human short-wavelength cones. Vision Research, 39, 2901-2927.
Stockman, A., & Sharpe, L. T. (2000). Spectral sensitivities of the middle- and long-wavelength sensitive cones derived from measurements in observers of known genotype. Vision Research, 40, 1711-1737.
