Figure 2. Wavelength discrimination assuming input intensity
is fixed
and known during color matching.
It is by maximum likelihood decoding of the cone responses
using the
simple model. The solid curve plots the discrimination threshold
as a
function of 
from the
model. The data points with error bars are the mean
and the
standard deviation 
of the
discrimination thresholds of the four observers of Pokorny and
Smith[1]. In fitting the model to the data,
is chosen
such that the quantity 
is
minimized.