International audience.
To test and improve the quality of color images, we need to knowhow the human visual system operates. Colorimetry is a method thatquantitatively assesses the changes that the engineer makes to an image.Recent advances in this field are due to a better understanding of visualmechanisms.This chapter first describes the physiological mechanisms that aretransferred from the retina in the eye to the human brain, which producethe physiological perception of color. Then it presents two approaches tocolorimetry: first, as recommended by the International Commission onIllumination (CIE), and second, deriving directly from the physiologyof the visual system that results in the ability to specify stimuli andcolor differences. Finally, the chapter outlines the difficulties in definingthe appearance of color and the advantages in modeling the humanvisual system.