The illumination in natural environments varies through the day. Stable inferences about
surface color might be supported by spatial ratios of cone excitations from the reflected light …

For some sets of surfaces, the spatial ratios of cone-photoreceptor excitations produced by
light reflected from pairs of surfaces are almost invariant under illuminant changes. These …

Colour constancy refers to the constant perceived or apparent colour of a surface despite
changes in illumination spectrum. Laboratory measurements have often found it imperfect …

Cone-contrast coordinates have proved useful for representing transient test stimuli used in
color vision experiments. These representations automatically take into account the spectral …

The visual stimulus associated with an object surface varies with the illumination falling on
the object. Constancy of perceived surface colour under changing illumination implies that …

The human visual system encodes the chromatic signals conveyed by the three types of
retinal cone photoreceptors in an opponent fashion. This opponency is thought to reduce …

We investigate how the amount of information about colors in natural scenes available to the
visual system depends on the spectral sensitivities of the three types of cones. We find that if …

Ratios of excitations in each cone–photoreceptor class produced by light reflected from pairs
of surfaces in a scene are almost invariant under natural illuminant changes. The stability of …

Quantitative measurements of perceptual colour constancy show that human observers
have a limited and variable ability to match coloured surfaces in scenes illuminated by …

Relational color constancy refers to the constancy of the perceived relations between the
colors of surfaces of a scene under changes in the spectral composition of the illuminant …