Human Colour Vision

Human Colour Vision

Human Colour Vision: 1. Colour Mixture and Retino-geniculate Processing

Normal humans can match any wavelength of light with a combination of three other wavelengths. This capacity, called trichromacy, is due to the presence of three types of cone photopigment in the photoreceptors. These photopigments differ in their peak absorption at either short (S), middle (M), or long (L) wavelengths. A match between two fields of differing spectral distribution occurs when t...

Human Colour Vision: 2. Colour Appearance and Cortical Transformations

Four terms (red, green, yellow, and blue) are necessary and sufficient to describe the appearance of hue. Parvo cells of the LGN respond maximally to modulation along either an S-(L+M) or an L-M axis, but few cells are tuned to intermediate directions. These axes do not correspond to the colour appearance axes. Colour appearance requires at least one more stage of processing, a stage that trans...

Computer Vision and Human Skin Colour

Computer vision based face and gesture recognition will allow future human computer interfaces to be more intuitive and user-friendly than traditional interfaces. A crucial processing step for the success of such systems is robust detection and tracking of faces and hands, which is frequently done by combining complementary cues, e.g., motion, shape, and colour. Skin colour is often used becaus...

Colour-Vision and Colour-Blindness