Kontrastempfindlichkeitsfunktion

Kontrastempfinden (contrast perception) is the visual system's ability to discern differences in luminance between adjacent areas. This perceptual faculty supports object recognition, reading, and navigation under varied lighting.

In psychophysics, contrast sensitivity is the reciprocal of the smallest detectable contrast. Two common metrics are Michelson contrast, used for patterns with roughly equal light and dark areas, and Weber contrast, used for small targets on a uniform background. The contrast sensitivity function describes sensitivity across spatial frequencies, typically showing higher sensitivity at mid-range frequencies and reduced sensitivity for very fine or very coarse patterns.

Neural processing involves both the retina and higher visual cortex. Lateral inhibition among retinal neurons enhances edge differences, while cortical neurons in primary visual cortex encode contrast signals contributing to conscious perception.

Factors influencing Kontrastempfinden include age, ocular diseases (such as cataract and glaucoma), lighting adaptation, motion, glare, and color context. Practical implications span display design, where contrast ratios affect legibility, and clinical assessment, where reduced contrast sensitivity can indicate visual impairment. Common clinical tests include letter or grating-based charts that measure contrast thresholds.

See also: contrast sensitivity function, luminance, visual acuity, spatial frequency.