Kell or Kell factor

Used to quantify the loss of vertical resolution in a line-scan imaging system due to artifacts of sampling.

Kanizsa-Minguzzi Anomalous Brightness Differentiation

(More on Optical Illusions)

Kanizsa Square

Illusory change in brightness created by surrounding figures. (More on Optical Illusions)

Keplerian View (of stereopsis)

Suggest two monocular views are projected point-by-point along diagonal rays and that their crossing-points are loci from which the depth of objects may be computed

Keratoconus

Keratoconus (conical cornea) is an recessive inherited condition that manifests as a thinning of the corneal apex, or central area of the cornea. With the weakening of the tissue there is a bulging of the tissue which increases the myopia of the affected eye.

Kinetic Depth Effect

(Wallach & O'Connell 1953)

When a wire shape is rotated behind a screen on which the shadow falls, observers are able to recover the structure from the motion and see the dynamic shadow pattern as a solid shape in motion.

Kluever-Bucy Syndrome

Seen in temporally lobectomized animals. They unnaturally tame, indiscriminately sexual and "psychially" blind. They can not recognize objects or learn to discriminate between them.

Koffka-Benussi Ring Illusion

The addition of an intervening line can chance the perceived lightness of the two sides of a ring with uniform luminance. (More on Optical Illusions)