Contrast sensitivity
The term contrast sensitivity is used in physics , medicine and perceptual psychology to describe visual perceptions .
The lower the contrast seen , the higher the contrast sensitivity, which is consequently defined as the reciprocal of the contrast. For example, if the smallest perceptible contrast is 20%, i.e. 0.2, this corresponds to a contrast sensitivity of 1 / 0.2 = 5.
Contrast sensitivity depends on many factors, one of which is the adaptation of the retina . It is lower under mesopic or scotopic conditions, i.e. during twilight or night vision, than under photopic (daytime) vision. A light-adapted eye can therefore perceive much smaller differences in luminance than a dark-adapted eye. The luminance of the background also influences the contrast sensitivity. For example, the stars in the sky can only be seen at night in the dark, but not in daylight. The reason for this is that only at night does the difference between the luminance of the stars and that of the sky lie above the light difference threshold. A similar example is a printed text that can only be read easily with adequate lighting, although the contrast of the letters is independent of the lighting. In order to achieve the highest contrast sensitivity, the luminance of the background must be between 3 and 3000 cd / m².
According to the results of a computer animation reproduced by Goldstein (2002), a newborn baby sees as if through a milk glass. This means that newborns cannot see fine details, but they can see relatively large objects with strong contrast.
Individual evidence
- ↑ Kienbaum, Jutta, Schuhrke, Bettina: Developmental Psychology of the Child From Birth to Age 12, Verlag W. Kohlhammer, Stuttgart, 2010, pp. 75–76