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Fig. 4.3
A basic human vision system schema
sensitive to long, medium, and short wavelengths (red, green, and blue), com-
monly known by their initials in English R, G, and B. The rods are located at the
outer edges of the retina and are responsible for vision in low light, being sensitive
only to shades of gray.
It can be concluded that the phenomenon of color depends on the nature of light
(light source), the interaction of light with materials, and the physiology of human
vision. In summary, the phenomenon of color perception is based on our body's
response to stimuli received from an electromagnetic radiation originated from a
light source, reflected or not for a given material and focusing on our eyes.
To standardize the identification of colors it is necessary to define some char-
acteristics of the light sources in order to standardize operating conditions. One is
the color temperature (CT), which expresses the appearance of the color of the light
emitted by the light source. Its unit of measurement is the Kelvin (K). The higher
the CT, the brighter the hue of a light's color. The correlated color temperature
(CCT) is defined as the temperature of the Planck radiator whose perceived radi-
ation more closely resembles that of a given stimulus with the same brightness
under specific observation conditions [ 4 ].
4.4 Color Analysis Using Image
The perception of an object (or of the acquired image of an object) is a function of
the spectral property of this object, the lighting, and its acquisition (human or not).
It is known that the phenomenon of color depends on the nature of light (light
source), the interaction of light with materials, and the physiology of human vision
(or image acquisition device). The phenomenon of color perception is based on the
body's response to stimuli received from an electromagnetic radiation originated
from a light source, reflected or not on a given material, focusing in the viewer's
eyes. Likewise, the acquired image of an object is a function of the spectral
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