The ability to see the world in colors is one of the important characteristics of the human visual system. The retina of the human eye includes specialized photoreceptors, called cones, which are responsible for the perception of colors. There are three types of cones that differ in the wavelength range of light they absorb; using the stimuli from these different cells, the human brain is able to create color perception. Most other animals only have rod cells, which are photoreceptors with better light sensitivity but that cover the full spectrum of visible light without color discrimination. In the human eye, rods are mainly located at the periphery of the retina, while the cones are concentrated in the central part.
In digital imaging, colors are generally reproduced by using the red, green, and blue additive primary colors. These have been selected because when they are combined together, they can produce a wide gamut of different colors. In fact, this choice of primaries...