Angol
In evolution, color vision has developed several times independently. The book does not cover all these forms of color vision but concentrates upon human color vision. Data from animal research is discussed for a better understanding of the human visual system. The prerequisite for color vision is the presence of light sensors (photoreceptors) that are differently excited by different wavelengths and a neuronal system that compares the excitation of the different photoreceptors. In the visual system photoreceptor excitation is compared in many different manners. As a result, color vision-being a modality in vision besides other modalities such as visual perception of form, motion, texture, depth etc.-is multi-modal in itself. Color processing takes place in the visual system at many different levels, from the photoreceptors to higher cortical areas.
