Color constancy investigated via partial hue-matching

Abstract

Each hue is believed to be made up of the four component hues (yellow, blue, red, and green). A hue consisting of just one component hue is called unitary (or unique). A new technique--partial hue-matching--has been used to reveal the component and unitary hues for a sample of 32 Munsell papers, which were illuminated by neutral, yellow, blue, green, and red lights and assessed by four normal trichromatic observers. The same set of four component hues has been found under both the neutral and the chromatic illuminations for all of the observers. On average, more than 87% of the papers containing a particular component hue under the neutral illumination also have this component hue when lit by the chromatic lights. However, only a quarter of the papers perceived as unitary under the neutral illumination continues being perceived as unitary under all of the chromatic illuminations. In other words, most unitary colors shift along the hue circle due to change in an illuminant's chromaticity. Still, this shift of unitary colors is relatively small: On average, it does not exceed one Munsell hue step.

On the colours dichromats see

“…The existence of these six component object‐colours has been confirmed recently using a new technique—partial hue‐matching . Moreover, it has also been confirmed that, firstly, each of the six component colours is experienced by trichromats as a unitary (unique) object colour; and each object colour can be described as a combination of a maximum of three component colours . A tertiary colour always contains an achromatic component.…”

“…52 Moreover, it has also been confirmed that, firstly, each of the six component colours is experienced by trichromats as a unitary (unique) object colour; and each object colour can be described as a combination of a maximum of three component colours. 53,54 A tertiary colour always contains an achromatic component. As the magnitude of each component in a compound colour varies continuously and independently, the object colours (of maximal purity) make a closed two-dimensional manifold of a spherical form.…”

“…[47][48][49][50][51] The major difference between the light colours and the object colours is that while the former are composed of the four component colours-yellow, blue, red and green-the latter include two more component coloursblack and white. [52][53][54] As a result, abstracting from brightness and saturation, the light-colour palette can be reduced to a hue palette that can be geometrically represented as a circle. The object-colour palette requires a two-dimensional sphere for its representation even though one abstract from the object-colours' purity.…”

Rethinking Colour Constancy

“…As one of several examples of this, an object perceived as having a unitary hue under neutral illumination might appear as being of a binary hue under a chromatic illumination. For instance, a Munsell chip perceived as unique yellow under neutral illumination has been found to appear as being greenish-yellow under a chromatic illumination [ 54 ]. In other words, an illuminant change generally results in a change in both the material and lighting colours.…”

The Optimal Color of Background Sheets for Microsurgery

“…Simultaneous contrast is due to differences in luminance, hue, and saturation between the object and background. After fixing one's eye on an object's color for a long time, the observer becomes aware of the complementary color (which is point-symmetric to the object's color in the hue circle [5]) afterimage. This undesirable phenomenon is known as successive contrast and referred to as the complementary afterimage phenomenon [2].…”